For Healthcare Providers Only. This reference is intended for use by emergency physicians, emergency medicine residents, paramedics, EMTs, poison control staff, and other licensed healthcare providers responding to suspected mushroom toxicity cases. It is not a guide for foragers or laypersons. For active poisoning cases, contact Poison Control at 1-800-222-1222 immediately for real-time case management support.
This guide covers sixteen clinically significant toxic mushroom species found in the Midwest United States (Ohio, Indiana, Illinois, Michigan, Wisconsin, Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, Kansas). Species are organized by toxicity tier: Tier 1 (Life-Threatening — amatoxin, orellanine), Tier 2 (Serious — gyromitrin, ibotenic acid/muscimol, illudin), and Tier 3 (Serious but not immediately life-threatening — GI toxins, muscarine, ibotenic acid/muscimol, psilocybin). The quick-reference table below provides rapid lookup by species; full clinical profiles follow.
Quick Reference — All 16 Species
| Common Name | Scientific Name | Toxin | Onset | Tier |
|---|---|---|---|---|
| Destroying Angel | Amanita bisporigera | Amatoxins (α-amanitin) | 6–24 hr (delayed) | Tier 1 — Life-Threatening |
| Death Cap | Amanita phalloides | Amatoxins (α-amanitin) | 6–24 hr (delayed) | Tier 1 — Life-Threatening |
| Autumn Skullcap | Galerina marginata | Amatoxins (α-amanitin) | 6–24 hr (delayed) | Tier 1 — Life-Threatening |
| Deadly Webcap | Cortinarius rubellus | Orellanine | 2–3 weeks (extreme delay) | Tier 1 — Life-Threatening |
| Deadly Dapperling | Pholiotina rugosa | Amatoxins (α-amanitin) | 6–24 hr (delayed) | Tier 1 — Life-Threatening |
| False Morel | Gyromitra esculenta | Gyromitrin (MMH) | 2–24 hr | Tier 2 — Serious |
| Fly Agaric | Amanita muscaria | Ibotenic acid / Muscimol | 30 min – 2 hr | Tier 2 — Serious |
| Panther Cap | Amanita pantherina | Ibotenic acid / Muscimol | 30 min – 2 hr | Tier 2 — Serious |
| Jack-o-Lantern | Omphalotus olearius / illudens | Illudin S / M | 30 min – 2 hr | Tier 2 — Serious |
| Ivory Funnel | Clitocybe dealbata | Muscarine | 15–30 min | Tier 3 — Caution |
| Fiber Caps | Inocybe spp. | Muscarine | 15–30 min | Tier 3 — Caution |
| Magic Mushrooms | Psilocybe spp. | Psilocybin / Psilocin | 15–60 min | Tier 3 — Caution |
| Lead Poisoner | Entoloma sinuatum | GI toxins (unknown) | 30 min – 4 hr | Tier 3 — Caution |
| Man on Horseback | Tricholoma equestre | Rhabdomyolysis (unknown) | 24–72 hr | Tier 3 — Caution |
| False Parasol | Chlorophyllum molybdites | GI toxins (molybdophyllysin) | 1–3 hr | Tier 3 — Caution |
Tier 1 — Life-Threatening
Amatoxin & Orellanine Species
These species cause potentially fatal hepatic failure, renal failure, or both. Critical feature: onset is delayed 6–24 hours (amatoxins) or 2–3 weeks (orellanine), making diagnosis challenging. All suspected ingestions require immediate Poison Control consultation and hospital admission. The apparent-recovery "honeymoon period" after initial GI symptoms must not result in premature discharge.
Destroying Angel
Amanita bisporigera
Tier 1 — Life-Threatening
GI phase: 6–24 hours post-ingestion. Organ failure: 2–4 days. ⚠
Identification Features
Entirely pure white — cap, gills, stalk, and spore print. Cap convex to flat, smooth, 5–12 cm. Prominent skirt-like ring (annulus) on the upper stalk. Bulbous base enclosed in a sac-like white volva — partially buried; always dig and examine the base. Grows singly in mixed deciduous and coniferous woods throughout the Midwest, summer through fall.
Onset Time
GI phase: 6–24 hours post-ingestion. Organ failure: 2–4 days.
Mechanism of Toxicity
Contains amatoxins, primarily α-amanitin, which irreversibly inhibits RNA polymerase II. This halts mRNA transcription and protein synthesis in hepatocytes and renal proximal tubule cells, causing progressive cell death. The cyclopeptide toxins are heat-stable, resistant to cooking, and undergo enterohepatic recirculation, prolonging toxin exposure.
Clinical Symptoms
Phase 1 — GI (6–24 hr)
- Severe nausea, profuse vomiting, watery/cholera-like diarrhea
- Abdominal cramping, dehydration, electrolyte disturbance
Phase 2 — Apparent Recovery (24–48 hr)
- GI symptoms subside — patient feels and appears improved
- This "honeymoon period" is a dangerous false recovery; hepatotoxic injury is progressing silently
Phase 3 — Organ Failure (2–4 days)
- Rapidly rising AST/ALT, often >10,000 U/L; jaundice
- Elevated PT/INR; coagulopathy; hepatic encephalopathy
- Acute tubular necrosis; oliguria; rising creatinine
- Fulminant hepatic and renal failure; can be fatal
Treatment Notes
Activated charcoal if presentation within 2 hours (delayed GI onset may extend this window — discuss with Poison Control). Aggressive IV fluid resuscitation for dehydration. Silibinin (IV, milk thistle extract) — inhibits hepatocyte uptake of amatoxins; available via compassionate use in the US (contact Poison Control for access guidance). High-dose Penicillin G IV may reduce hepatic amatoxin uptake. Serial LFTs, PT/INR, BMP every 6–12 hours. Early hepatology and transplant surgery consultation. Liver transplantation may be the only definitive therapy in fulminant failure. Do not discharge any suspected amatoxin ingestion during the apparent-recovery phase — admit all cases for observation.
⚠ Look-Alike Warning: Commonly confused with Button Mushrooms (Agaricus bisporus), Meadow Mushrooms (Agaricus campestris), and the Paddy Straw Mushroom (Volvariella volvacea). Key differentiator: edible Agaricus species have pink to chocolate-brown gills (not white) and no volva cup at the base. The white volva of the Destroying Angel is the critical safety feature — always dig up the base before eating any white mushroom.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Death Cap
Amanita phalloides
Tier 1 — Life-Threatening
GI phase: 6–24 hours. Hepatic failure: 2–4 days. ⚠
Identification Features
Cap pale greenish-yellow to olive-green, occasionally white-washed, smooth, 5–15 cm. Gills white and free from the stalk. White skirt-like ring (annulus) on upper stalk. White sac-like volva at base — often partially underground; always dig to examine. White spore print. Grows in association with oaks, chestnuts, and other hardwoods; introduced to the Midwest via imported nursery stock and expanding its range.
Onset Time
GI phase: 6–24 hours. Hepatic failure: 2–4 days.
Mechanism of Toxicity
Identical to Destroying Angel: amatoxins (primarily α-amanitin) inhibit RNA polymerase II, causing progressive hepatocyte and renal tubular cell death. Also contains phallotoxins (primarily phallodin), which cause GI irritation. Responsible for approximately 90% of fatal mushroom poisonings worldwide. Lethal dose estimated at 5–7 mg amanitin — approximately half a cap of a mature specimen (≈35g fresh weight).
Clinical Symptoms
Phase 1 — GI (6–24 hr)
- Severe nausea, vomiting, profuse watery diarrhea
- Abdominal cramping, dehydration
Phase 2 — Apparent Recovery (24–48 hr)
- GI symptoms partially resolve — dangerous false improvement
- Liver enzymes begin to rise during this phase
Phase 3 — Hepatorenal Failure (2–4 days)
- Fulminant hepatic failure: AST/ALT often >10,000 U/L, jaundice, coagulopathy, encephalopathy
- Acute kidney injury; may require dialysis
- Multi-organ failure; potentially fatal without transplant
Treatment Notes
Same as Destroying Angel: activated charcoal (if within window per Poison Control guidance), aggressive IV fluids, silibinin IV (compassionate use — contact Poison Control), high-dose Penicillin G IV. Serial LFTs, coagulation studies, and renal function every 6–12 hours. Early hepatology consultation. Early liver transplant evaluation — transplant listing criteria should be applied promptly (King's College criteria or equivalent). The apparent-recovery phase must not result in premature discharge.
⚠ Look-Alike Warning: Most commonly confused with Paddy Straw Mushroom (Volvariella volvacea) — a food staple in Southeast Asian cuisine, frequently misidentified in immigrant communities across the Midwest. Also confused with edible puffballs when young (button stage) — cross-section of a button-stage Amanita reveals the outline of the developing cap structure, distinguishing it from a true puffball. Greenish cap coloration can also cause confusion with edible species.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Autumn Skullcap
Galerina marginata
Tier 1 — Life-Threatening
6–24 hours (same delayed pattern as Amanita poisoning). ⚠
Identification Features
Small mushroom, cap 1–4 cm, smooth, tawny-brown to orange-brown, often hygrophanous (color changes as it dries). Gills close, adnate to slightly decurrent, pale brown. Ring (annulus) present on upper stalk, often collapsing with age. Rusty-brown spore print (critical differentiator from honey mushrooms). Grows in clusters or scattered on dead wood — logs, stumps, and buried wood — throughout the Midwest, summer through late fall.
Onset Time
6–24 hours (same delayed pattern as Amanita poisoning).
Mechanism of Toxicity
Contains the same amatoxins as Amanita species — primarily α-amanitin — despite its small size and unassuming appearance. Concentration of amatoxins per gram of tissue can be as high as in death cap. The mechanism is identical: inhibition of RNA polymerase II causing progressive hepatocellular and renal tubular cell death.
Clinical Symptoms
GI Phase (6–24 hr)
- Nausea, vomiting, diarrhea — same delayed presentation as Amanita amatoxin poisoning
Hepatotoxic Phase (2–4 days)
- Elevated hepatic transaminases; jaundice; coagulopathy
- Hepatic failure; acute kidney injury
- Fulminant course possible, particularly in small children where a relatively small number of mushrooms constitutes a lethal dose
Treatment Notes
Identical to amatoxin protocol: activated charcoal if within window, aggressive IV hydration, silibinin IV if available, high-dose Penicillin G. Serial hepatic and renal function monitoring. Early hepatology consultation. Even small ingestions must be treated as potentially lethal — the amatoxin content of a few Galerina can be sufficient for fatal toxicity in a child or small adult. Do not estimate dose from mushroom size alone; treat all ingestions as high-risk.
⚠ Look-Alike Warning: The single most dangerous look-alike confusion in the Midwest: Honey Mushrooms (Armillaria mellea and related species) are edible and highly sought by foragers. Both grow in clusters on wood, have a ring on the stalk, and are similar in color. The critical differentiator is the spore print: Honey Mushrooms produce a white spore print; Galerina marginata produces a rusty-brown to cinnamon spore print. A spore print is mandatory before eating any wood-inhabiting LBM ('little brown mushroom'). Also confused with edible Pholiota species.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Deadly Webcap
Cortinarius rubellus
Tier 1 — Life-Threatening
Renal failure onset: 2–3 weeks after ingestion (range: 3 days to 3 weeks). This extreme delay is the most clinically dangerous feature — the link to mushroom ingestion is almost universally missed. ⚠
Identification Features
Cap reddish-brown to tawny-orange, conical to broadly umbonate, dry, 3–8 cm. Gills attached, rusty-brown (matching the spore print). Cobweb-like cortina veil — a filamentous partial veil connecting the cap margin to the stalk in young specimens; leaves rusty spore-stained fibers on the stalk in mature ones. Stalk stout, fibrous, same color as cap. Grows in coniferous and mixed forest, particularly with spruce and fir, across the upper Midwest and Great Lakes region.
Onset Time
Renal failure onset: 2–3 weeks after ingestion (range: 3 days to 3 weeks). This extreme delay is the most clinically dangerous feature — the link to mushroom ingestion is almost universally missed.
Mechanism of Toxicity
Contains orellanine, a bipyridyl nephrotoxin. Orellanine undergoes slow metabolic activation and causes selective destruction of renal proximal tubular cells. Its mechanism involves inhibition of protein phosphatase activity and generation of free radicals in renal tissue. The extreme latency of toxicity — weeks, not hours — makes clinical diagnosis exceptionally challenging; patients, families, and clinicians rarely connect renal failure to a mushroom meal weeks prior.
Clinical Symptoms
Early Phase (2–3 days)
- Mild GI symptoms: nausea, vomiting, abdominal discomfort
- These may be minimal or absent — easily dismissed
Delayed Nephrotoxic Phase (2–3 weeks after ingestion)
- Progressive renal failure: oliguria, rising creatinine and BUN
- Polydipsia, polyuria (early tubular dysfunction)
- Flank pain, headache, fatigue
- Severe cases: dialysis-dependent renal failure, permanent renal insufficiency
Treatment Notes
No specific antidote. Supportive renal care: aggressive hydration when diagnosed early, management of electrolyte imbalances, close nephrology follow-up. Dialysis for acute kidney injury — may be required for weeks to months. Transplant evaluation for irreversible renal failure. Clinical key: ask all patients presenting with unexplained acute renal failure about wild mushroom ingestion in the past 3–4 weeks. Orellanine can be detected in urine/serum by some reference laboratories. Early identification changes the clinical trajectory by enabling supportive care before complete renal shutdown.
⚠ Look-Alike Warning: Confused with various edible brown-capped mushrooms. Related and similarly toxic species include Cortinarius orellanus. The cobweb-like cortina veil is a genus-level identifier — any Cortinarius species must be considered potentially toxic. Particularly dangerous when confused with edible chanterelles, or gathered by foragers with limited experience who do not recognize the cortina.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Deadly Dapperling
Pholiotina rugosa
Tier 1 — Life-Threatening
6–24 hours (delayed onset) — same biphasic course as Death Cap ⚠
Identification Features
Very small (cap 1–3 cm), honey-brown to cinnamon-brown, convex to flat. Gills cinnamon-brown. Slender stem with a fragile membranous ring (annulus). Grows in lawns, mulch beds, disturbed soil, parks, and gardens across the Midwest — ubiquitous in suburban settings. Spore print rusty-cinnamon-brown. Also known as Conocybe filaris or Deadly Conocybe. Easily overlooked among other lawn mushrooms.
Onset Time
6–24 hours (delayed onset) — same biphasic course as Death Cap
Mechanism of Toxicity
Amatoxins (α-amanitin and β-amanitin) — inhibit RNA polymerase II, causing progressive hepatocellular necrosis. Despite its tiny size, amatoxin concentration per gram of fresh tissue is comparable to Death Cap. A child ingesting a few specimens from a lawn can receive a lethal dose.
Clinical Symptoms
Phase 1 — GI (6–24 hr): Nausea, vomiting, abdominal pain, watery diarrhea. Phase 2 — Apparent improvement (24–48 hr): Patient may seem to improve; do NOT discharge during this window. Phase 3 — Hepatorenal failure (48–96+ hr): Rising transaminases, coagulopathy, jaundice; renal tubular necrosis possible; fulminant hepatic failure.
Treatment Notes
Full amatoxin protocol identical to Amanita species: activated charcoal if within 1–2 hours of ingestion and airway protected; aggressive IV fluid hydration; serial LFTs, PT/INR, BMP every 6–12 hours; hepatology and nephrology consultation; silibinin IV (compassionate use — call Poison Control immediately); early liver transplant evaluation per King's College or equivalent criteria.
⚠ Look-Alike Warning: Most dangerously confused with edible Fairy Ring Mushroom (Marasmius oreades), which also grows in lawn rings. Marasmius has widely spaced, tough gills and NO fragile ring. Any small brown mushroom with a ring growing in a lawn or mulch bed must be considered potentially amatoxin-containing — this is a major pediatric lawn risk across the Midwest.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Tier 2 — Serious
CNS, Hemolytic & GI Toxin Species
These species cause serious, sometimes severe toxicity, but have lower overall mortality than Tier 1 species with appropriate supportive care. Onset is faster (30 minutes to 24 hours), aiding diagnosis. All confirmed or suspected ingestions warrant emergency evaluation, IV fluids, and Poison Control consultation.
False Morel
Gyromitra esculenta
Tier 2 — Serious
2–24 hours (most GI symptoms within 6–8 hours).
Identification Features
Cap irregularly brain-like or saddle-shaped, wrinkled and lobed, reddish-brown to dark brown, 5–15 cm. Not honeycomb-pitted — key distinction from true morels. Cap surface folded and convoluted, not ridged in a regular grid pattern. Stalk white to pale, irregular, sometimes furrowed, often chambered internally. Grows in spring in sandy coniferous forest soils and forest edges across the Midwest, particularly under pines. Peak season coincides with true morel season.
Onset Time
2–24 hours (most GI symptoms within 6–8 hours).
Mechanism of Toxicity
Contains gyromitrin, which hydrolyzes to monomethylhydrazine (MMH) — a volatile, water-soluble toxin also present in rocket fuel. MMH causes direct oxidative hemolysis, inhibits pyridoxal phosphate (vitamin B6) metabolism (similar to isoniazid toxicity), and is hepatotoxic in large doses. Some gyromitrin is lost in cooking or drying, leading to the misconception that this species is safe when cooked — this is unreliable.
Clinical Symptoms
Early (2–24 hr)
- Nausea, vomiting, watery diarrhea, abdominal cramping
- Headache, dizziness, weakness
Hemolytic Phase (variable)
- Hemolytic anemia: pallor, weakness, dark urine (hemoglobinuria)
- Methemoglobinemia: cyanosis, dyspnea, tachycardia
Severe/Delayed (rare)
- Hepatic failure in large ingestions
- Seizures (pyridoxine depletion)
- Rarely fatal but potentially severe
Treatment Notes
Supportive care: IV fluids, antiemetics. Methylene blue 1–2 mg/kg IV for symptomatic methemoglobinemia — monitor pulse oximetry (standard SpO2 may read falsely normal with MetHb; use co-oximetry). Pyridoxine (Vitamin B6) 25 mg/kg IV may reduce MMH toxicity and treat seizures via the same mechanism as isoniazid-induced pyridoxine depletion. Monitor CBC for hemolysis, LFTs for hepatotoxicity. Activated charcoal if early presentation. Transfusion for severe hemolytic anemia.
⚠ Look-Alike Warning: The primary look-alike confusion is with true edible Morel Mushrooms (Morchella spp.). True morels have a honeycomb-pitted cap with regular ridges and pits; False Morels have irregular brain-like folds. True morels are also entirely hollow when cut in half longitudinally; False Morels have a chambered or solid interior. Both fruit in spring in similar habitats across the Midwest.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Fly Agaric
Amanita muscaria
Tier 2 — Serious
30 minutes to 2 hours.
Identification Features
Cap bright red to orange-red (sometimes fading to orange or yellow in sun), 8–20 cm. White warts (patches) on cap surface — remnants of the universal veil; may wash off in rain. Gills white, free. Ring present on upper stalk; stalk base bulbous with remnant volva. White spore print. Grows in association with birch, pine, and spruce across the Midwest, summer through fall.
Onset Time
30 minutes to 2 hours.
Mechanism of Toxicity
Contains ibotenic acid and muscimol. Ibotenic acid is a glutamate receptor agonist (NMDA/AMPA); muscimol is a potent GABA-A receptor agonist and is the primary psychoactive compound (5–10× more potent than ibotenic acid, formed during drying/metabolism). Also contains trace muscarine — clinically insignificant in this species. The syndrome is primarily CNS and does NOT include the cholinergic toxidrome seen with true muscarine poisoning.
Clinical Symptoms
CNS Effects (30 min – 2 hr)
- Confusion, disorientation, delirium
- Visual and auditory hallucinations (often described as dreamlike)
- Ataxia, dysarthria, lethargy progressing to drowsiness
- Hypersalivation, lacrimation, diaphoresis (mild muscarinic effects)
Severe Cases
- Myoclonic jerking, seizures (rare)
- Coma — typically resolves within 12–24 hours without permanent sequelae
Treatment Notes
Primarily supportive. Benzodiazepines (diazepam or lorazepam) for agitation and seizure control. Quiet, calm environment. Do NOT administer physostigmine — it can worsen CNS depression and cause cholinergic crisis in this clinical context. Atropine is not indicated (muscarinic effects are minor and self-limiting). Most patients recover fully within 6–24 hours. Admission for observation recommended for severe agitation or altered mental status.
⚠ Look-Alike Warning: Rarely confused with edible species due to distinctive coloration. However, the yellow-capped variety (Amanita muscaria var. guessowii) and related species can cause confusion. Young button-stage specimens might be confused with edible puffballs — cross-section will reveal cap outline. Amanita muscaria is also of concern due to intentional ingestion for psychoactive effects, particularly in adolescents.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Panther Cap
Amanita pantherina
Tier 2 — Serious
30 minutes to 2 hours.
Identification Features
Cap brown to dark sepia-brown, 5–12 cm, smooth with small white warts (more persistent than those of Fly Agaric). Gills white, free. Ring on upper stalk, often striate on upper surface. Basal bulb with a distinct collar-like rim (gutter) rather than a loose volva cup — an important structural difference from Death Cap. White spore print. Grows in mixed forests, particularly with beech and oak, across the Midwest, summer through fall.
Onset Time
30 minutes to 2 hours.
Mechanism of Toxicity
Contains higher concentrations of ibotenic acid and muscimol than Fly Agaric — clinically produces a more severe and consistent toxidrome. Some sources report an anticholinergic-like syndrome (dry skin, urinary retention, tachycardia, mydriasis) in addition to the central CNS effects, though the primary mechanism is GABA-ergic and glutamatergic, not anticholinergic. Muscimol is the principal active toxin.
Clinical Symptoms
CNS Effects (30 min – 2 hr)
- Confusion, delirium, agitation — typically more severe than Fly Agaric
- Hallucinations, disorientation, ataxia
- Hypersalivation, miosis or mydriasis (variable)
Anticholinergic-Like Features (variable)
- Dry flushed skin, urinary retention, tachycardia
- These features can cause diagnostic confusion with classic anticholinergic poisoning
Severe Cases
- Myoclonus, seizures, coma — more common than with Fly Agaric
Treatment Notes
Supportive care. Benzodiazepines for agitation and seizures. Do NOT administer physostigmine. If anticholinergic features dominate, physostigmine may seem clinically indicated but is contraindicated given the ibotenic acid/muscimol mechanism — benzodiazepines are safer for agitation. Admission for monitoring. Most patients recover within 12–24 hours.
⚠ Look-Alike Warning: Confused with edible Blusher (Amanita rubescens), which also has white warts on a darker cap. Critical differentiator: A. rubescens flesh stains pinkish-red when cut or bruised ('blushes'); Panther Cap flesh remains white. Also confused with edible varieties of brown-capped Amanita. All Amanita species with white warts must be approached with extreme caution.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Jack-o-Lantern
Omphalotus olearius / illudens
Tier 2 — Serious
30 minutes to 2 hours.
Identification Features
Cap bright orange to deep orange-yellow, smooth, 5–20 cm. Gills bright orange — a key differentiator from chanterelles, which have forked ridges, not true gills. Grows in dense clusters at the base of hardwood trees (especially oaks), or from buried roots — never scattered in open soil. Gills may bioluminesce faintly green in complete darkness. White spore print. Very common across the Midwest throughout summer and fall. Eastern North American species is O. illudens; European species O. olearius — both cause identical toxidromes.
Onset Time
30 minutes to 2 hours.
Mechanism of Toxicity
Contains illudin S and illudin M — sesquiterpene toxins that are GI irritants. Mechanism involves DNA damage through alkylation in rapidly dividing cells; GI mucosal cells are particularly vulnerable. Not life-threatening but causes prompt, severe GI illness.
Clinical Symptoms
GI Effects (30 min – 2 hr)
- Severe nausea and repetitive vomiting
- Profuse, watery diarrhea
- Abdominal cramping, diaphoresis
- Significant dehydration — particularly in elderly and pediatric patients
Course
- Symptoms typically resolve within 6–24 hours
- Not directly life-threatening but severe enough to require emergency evaluation
- No hepatic or renal toxicity
Treatment Notes
Supportive: aggressive IV fluid replacement for dehydration. Antiemetics (ondansetron, prochlorperazine). Monitor electrolytes; replace as needed. Admission for IV fluids typically required for severe vomiting. No antidote, no antitoxin. Full recovery expected.
⚠ Look-Alike Warning: The most common dangerous look-alike confusion in the Midwest — Jack-o-Lanterns are routinely mistaken for Golden Chanterelles (Cantharellus cibarius and related species), one of the most prized edible mushrooms. Key differentiators: (1) Chanterelles have forked, blunt-edged, false ridges (not true blade-like gills) running partway down the stalk; Jack-o-Lanterns have true sharp, blade-like gills. (2) Chanterelles grow singly or scattered in soil; Jack-o-Lanterns grow in dense clusters from wood or roots. (3) Chanterelle caps are irregular and wavy-edged; Jack-o-Lanterns have smoother, more regular caps.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
⚠ Tier 3 — Caution Advised
Tier 3 — Serious but Not Immediately Life-Threatening
The species below cause significant toxicity requiring emergency evaluation and hospital visits. They contain GI toxins, muscarine (cholinergic syndrome), ibotenic acid/muscimol (CNS effects), or psilocybin (perceptual disturbances). Fatalities are rare in healthy adults with supportive care, but severity can be serious. All suspected ingestions should be reported to Poison Control (1-800-222-1222). Pediatric and medically compromised patients face higher risk.
Ivory Funnel
Clitocybe dealbata
Tier 3 — Caution
Onset 15–30 min
Identification Features
Small white to pale gray mushroom, 2–5 cm cap, funnel-shaped with incurved margin. Gills white to cream, decurrent (running down the stem). Grows in lawns, grassy areas, and meadows — often in fairy rings. Easily confused with edible fairy ring mushroom (Marasmius oreades) and other small white fungi. No distinctive odor. Spore print white.
Onset Time
15–30 minutes post-ingestion. Rapid onset is diagnostically useful — muscarinic symptoms within 30 minutes of eating strongly suggest this species or Inocybe spp. Duration: 2–6 hours.
Mechanism of Toxicity
Muscarine — a stable, heat-resistant quaternary ammonium compound that activates muscarinic acetylcholine receptors (M1–M5) in the autonomic nervous system. Acts peripherally (does not cross BBB). Causes cholinergic overstimulation of exocrine glands, smooth muscle, and the heart.
Clinical Symptoms
SLUDGE/DUMBELS syndrome: Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis; Diaphoresis (profuse sweating), Urinary incontinence, Miosis, Bradycardia, Bronchospasm, Excessive secretions, Lacrimation, Seizures (rare). Bradycardia and bronchospasm are the life-threatening features in large ingestions.
Treatment Notes
Atropine is the specific antidote — titrate to dry secretions (not to heart rate). Start with 0.5–2 mg IV in adults; repeat every 5–10 minutes as needed. Severely poisoned patients may require large cumulative doses. Do not use pralidoxime (muscarine is not an organophosphate; reactivators are ineffective). Supportive care: IV fluids, O₂, bronchodilators for bronchospasm. Monitor cardiac rhythm. Contact Poison Control for dosing guidance.
⚠ Look-Alike Warning: Frequently confused with edible Fairy Ring Mushroom (Marasmius oreades) and edible Lepista species. Marasmius has tougher, non-decurrent gills and grows on a wiry stem. Any small white mushroom from a lawn or meadow should be considered potentially muscarine-containing.
Fiber Caps
Inocybe species (I. erubescens, I. geophylla, I. rimosa)
Tier 3 — Caution
Onset 15–30 min
Identification Features
Medium-small brown mushrooms with distinctly fibrous (silky-radially streaked) caps. Inocybe is a large genus with 400+ species, most toxic. Cap 2–8 cm, tan to brown, often with central umbo; surface splits radially with age. Gills pale then clay-brown (matching spore color). Brown spore print — distinctive. Spicy or earthy odor in some species. Grows in mixed woodland throughout the Midwest, summer–fall.
Onset Time
15–30 minutes post-ingestion. Same rapid cholinergic presentation as Clitocybe dealbata. I. erubescens contains some of the highest muscarine concentrations of any fungus.
Mechanism of Toxicity
Muscarine — same mechanism as Ivory Funnel above. Inocybe erubescens (Deadly Fiber Cap / Brick-Red Tear Sheet) is the most clinically significant species — muscarine content is very high, and accidental ingestion has caused fatalities. Most other Inocybe species contain lower but still significant muscarine.
Clinical Symptoms
Identical cholinergic syndrome to Clitocybe dealbata: profuse sweating, salivation, lacrimation, miosis, vomiting, diarrhea, bradycardia, bronchospasm. Severity depends on muscarine load — I. erubescens can cause severe, life-threatening cholinergic crisis.
Treatment Notes
Atropine IV — same protocol as Ivory Funnel. May require higher doses for I. erubescens ingestion due to higher muscarine burden. Monitor respiratory status closely — bronchospasm can be severe. Consider ICU admission for moderate-severe cholinergic crisis. Cardiac monitoring mandatory (bradycardia, heart block possible).
⚠ Look-Alike Warning: Commonly confused with edible Chanterelles (brown coloration, woodland habitat) and other small brown woodland mushrooms. The fibrous cap texture and brown spore print are key identifiers. Any brown woodland mushroom with muscarinic symptoms within 30 min of eating: presumptively treat as muscarine poisoning.
Magic Mushrooms
Psilocybe species (P. cyanescens, P. semilanceata and others)
Tier 3 — Caution
Onset 15–60 min
Identification Features
Small to medium mushrooms with hygrophanous brown to caramel caps; blue-staining on bruising (a key field indicator caused by oxidation of psilocin). Cap 1–5 cm, conical to bell-shaped to broadly convex. Gills gray to dark purple-brown. Purple-brown to dark brown spore print. Grows in mulched garden beds, woodchip piles, grassy areas, and disturbed ground throughout the Midwest.
Onset Time
15–60 minutes post-ingestion (faster when taken in tea form). Peak at 1–2 hours; duration 4–8 hours. Clinical course is predictable based on dose.
Mechanism of Toxicity
Psilocybin → Psilocin (dephosphorylation by alkaline phosphatase). Psilocin is a serotonin 5-HT2A receptor agonist causing CNS effects. ER presentations typically involve acute anxiety, panic, adverse psychological reactions ("bad trip"), or accidental ingestion by children or adults unaware of the substance.
Clinical Symptoms
Perceptual distortions (visual/auditory hallucinations), altered time perception, euphoria or anxiety/panic, confusion, tachycardia, mild hypertension, mydriasis (pupil dilation). Hyperthermia in rare cases (high dose or agitated delirium). No significant anticholinergic, cholinergic, or GI toxidrome. Typically self-limiting.
Treatment Notes
Primarily supportive and reassurance-based. Place patient in calm, quiet environment with a reassuring attendant ("talk-down"). Benzodiazepines (lorazepam or diazepam) for severe agitation or anxiety — first-line. Avoid antipsychotics as first-line (haloperidol may lower seizure threshold; olanzapine if needed for refractory agitation). Monitor vitals. Cyproheptadine (serotonin antagonist) for suspected serotonin syndrome features. Most cases resolve within 6–8 hours without intervention beyond reassurance and monitoring.
⚠ Look-Alike Warning: Psilocybe species can be confused with deadly Galerina marginata (Autumn Skullcap), which grows in similar habitats, has a similar brown cap, and produces a brown spore print. Blue-staining on bruising is absent in Galerina. Any unclear brown mushroom from woodchip mulch: consider Galerina toxicity and evaluate with delayed (6–24 hr) onset protocol.
Lead Poisoner
Entoloma sinuatum (syn. E. lividum)
Tier 3 — Caution
Onset 30 min – 4 hr
Identification Features
Large, robust mushroom, cap 6–20 cm, pale gray-tan to whitish, smooth surface. Gills initially pale yellow, aging to salmon-pink (pink spore print). Pink spore print is the key identifier — critical differentiator. Mealy (flour-like) odor and taste. Grows in deciduous woodland, particularly near oaks. One of Europe's most common causes of mushroom GI poisoning; increasingly encountered in Midwest foraging regions.
Onset Time
30 minutes to 4 hours post-ingestion. GI symptoms can be severe and prolonged (up to 24–48 hours). Dehydration from vomiting/diarrhea may require IV rehydration.
Mechanism of Toxicity
GI toxins — exact chemical nature incompletely characterized. Compounds include peptides and low-molecular-weight toxic substances that cause direct gastric and intestinal irritation. No systemic organ damage in typical cases. Severity is dose-dependent.
Clinical Symptoms
Severe nausea, profuse vomiting (often violent), watery diarrhea, abdominal cramping. Dehydration and electrolyte disturbance in serious cases. No hepatic or renal involvement. No CNS effects. Symptoms typically resolve within 24–48 hours with supportive care.
Treatment Notes
Supportive care: IV fluids for dehydration, anti-emetics (ondansetron preferred), electrolyte replacement. Activated charcoal if within 1–2 hours. Hospitalization may be needed for severe dehydration, particularly in elderly or pediatric patients. No antidote; prognosis excellent with hydration.
⚠ Look-Alike Warning: Frequently confused with edible St. George's Mushroom (Calocybe gambosa) and Field Mushroom (Agaricus campestris). The key differentiator is the pink spore print of Entoloma — Agaricus has chocolate-brown spores; Calocybe has white spores. The mealy smell can also suggest edible species. Always obtain a spore print before consuming any large pale woodland mushroom.
Man on Horseback
Tricholoma equestre (syn. T. flavovirens)
Tier 3 — Caution
Onset 24–72 hr (rhabdomyolysis)
Identification Features
Cap 5–12 cm, yellow-green to greenish-brown, often with olive or brownish center; sticky when moist. Gills bright sulfur-yellow — distinctive. Stalk white to yellowish, stout. White spore print. Grows under conifers (particularly pine) in sandy soils, late summer through fall. Historically considered edible in Europe; now recognized as toxic after multiple fatalities in France (1992–2000).
Onset Time
24–72 hours after consumption of multiple meals over several days. The rhabdomyolysis syndrome is associated with repeated large ingestions (3+ consecutive meals), not a single serving. Delayed presentation can complicate diagnosis.
Mechanism of Toxicity
Rhabdomyolysis — toxic compound(s) not fully identified; cyclohexenone derivatives are suspected. Causes direct skeletal muscle damage and myocyte lysis with repeated large ingestions. Results in myoglobinuria and risk of acute kidney injury from myoglobin nephrotoxicity.
Clinical Symptoms
Fatigue, muscle weakness, myalgia (muscle pain), dark urine (myoglobinuria). Elevated CK (often dramatically elevated — >10,000 U/L in severe cases). Elevated AST/LDH reflecting muscle damage. Potential acute kidney injury. Cardiotoxicity (myocarditis) reported in the original French outbreak. Fever and leukocytosis possible.
Treatment Notes
Aggressive IV hydration to protect kidneys from myoglobin precipitation (target urine output ≥1 mL/kg/hr). Serial CK, creatinine, electrolytes (hyperkalemia from muscle lysis), and urine myoglobin. Discontinue all statin use (compounds rhabdomyolysis risk). Dialysis if renal failure develops. Cardiac monitoring if myocarditis suspected. Consult nephrology and Poison Control early. No specific antidote — supportive care is definitive.
⚠ Look-Alike Warning: Historically consumed as a prized edible in France and Eastern Europe. Foragers familiar with European traditions may not recognize it as toxic. Distinguish from edible Chanterelles (no true gills; ridges not sulfur-yellow) and other yellow Tricholoma species. Any patient presenting with unexplained rhabdomyolysis should be asked about recent wild mushroom consumption over the past 3–5 days.
False Parasol (Green-Spored Parasol)
Chlorophyllum molybdites
Tier 3 — Caution
Onset 1–3 hr
Identification Features
Large mushroom (cap 10–30 cm), white to pale tan with brownish fibrous scales and a prominent double ring. Gills initially white, turning green at spore maturity. Green spore print — the definitive identifier. Grows in lawns, parks, suburban yards, golf courses, and disturbed grassy areas across the entire Midwest, particularly after summer rains. Among the most common toxic mushrooms in North America by volume of poisoning calls — the #1 cause of mushroom GI poisoning in many Midwest poison control centers.
Onset Time
1–3 hours post-ingestion. Rapid, intense GI onset. Symptoms typically resolve within 6–12 hours with supportive care. Pediatric and elderly patients at higher risk for dehydration.
Mechanism of Toxicity
GI irritants — molybdophyllysin (a zinc metalloprotease) and other heat-stable toxins cause direct gastrointestinal epithelial irritation and toxicity. Unlike the Destroying Angel, there is no organ-failure toxidrome. The toxin is not amatoxin or orellanine.
Clinical Symptoms
Explosive nausea, vomiting, profuse watery to bloody diarrhea, abdominal cramping. Dehydration and electrolyte imbalance in severe cases. Symptoms typically self-limited within 6–12 hours. Hypotension from volume depletion possible. Liver and kidney function are NOT typically affected — onset within 3 hours effectively rules out amatoxin poisoning.
Treatment Notes
Supportive care: IV hydration, antiemetics, electrolyte replacement. No antidote. Monitor and replace fluid losses — patients with profuse vomiting and diarrhea can dehydrate rapidly. Symptoms typically resolve within 12 hours. The rapid onset (1–3 hours) is diagnostically helpful — amatoxin poisoning (Death Cap, Galerina) has a minimum 6-hour onset. If GI symptoms begin within 3 hours of eating, amatoxin poisoning is extremely unlikely, though not fully excluded.
⚠ Look-Alike Warning: Most dangerously confused with the edible Shaggy Parasol (Chlorophyllum rhacodes) and edible Parasol Mushroom (Macrolepiota procera) — all are large, scaly-capped lawn or meadow mushrooms with rings. The green spore print is the definitive differentiator: edible parasols have a white spore print. Also confused with edible Agaricus species; Agaricus has brown (not green) gills and spores. Advise foragers: always take a spore print before eating any large parasol-shaped mushroom.
Look-Alike Comparison Table — Dangerous vs. Edible
The following pairs represent the most clinically significant identification confusions in the Midwest. Accurate species identification by foragers is often the proximate cause of mushroom poisonings — these comparisons are provided for clinician reference to understand the mechanism of error.
| Dangerous Species | Commonly Confused With (Edible) | Key Differentiating Features |
|---|---|---|
| Destroying Angel Amanita bisporigera |
Button / Meadow Mushroom Agaricus bisporus / campestris |
Destroying Angel: pure white gills throughout; white volva cup at base. Agaricus: gills turn pink then chocolate-brown; no volva cup. Always dig up the base. |
| Death Cap Amanita phalloides |
Paddy Straw Mushroom Volvariella volvacea |
Death Cap: white gills; ring on stalk; volva at base. Paddy Straw: free pink gills; no ring; volva present but egg-shaped. Death Cap: spore print white. Straw mushroom: pink spore print. |
| Autumn Skullcap Galerina marginata |
Honey Mushroom Armillaria mellea |
Autumn Skullcap: rusty-brown spore print. Honey Mushroom: white spore print. Both grow in clusters on wood; both have a ring. Spore print is mandatory before eating any wood-growing LBM. |
| Deadly Webcap Cortinarius rubellus |
Various edible brown mushrooms; Golden Chanterelle | Cortinarius spp.: rusty-brown spore print; remnant cobweb (cortina) fibers on stalk. Edible species: varied (check spore print). Any brown mushroom with rusty-brown spores and fibrous stalk fibers is suspect for Cortinarius. |
| False Morel Gyromitra esculenta |
True Morel Morchella spp. |
False Morel: brain-like, irregular folds and lobes; stalk often chambered. True Morel: regular honeycomb of ridges and pits; cap and stalk entirely hollow when cut longitudinally. Confusion is most dangerous in spring when both species fruit simultaneously. |
| Jack-o-Lantern Omphalotus illudens |
Golden Chanterelle Cantharellus cibarius |
Jack-o-Lantern: true sharp blade-like gills; grows in dense clusters from wood. Chanterelle: forked blunt false-ridges (not true gills) running partway down stalk; grows singly in soil. This is the most common dangerous look-alike confusion for Midwest foragers. |
| Fly Agaric / Panther Cap Amanita muscaria / pantherina |
Puffballs (button stage) | All Amanita species in button (egg) stage resemble puffballs. Cross-section of any egg-stage white mushroom: true puffball = solid white interior throughout; button-stage Amanita = visible cap, gills, and stalk outline within. Always cross-section before consuming any puffball. |
Midwest Regional Notes — Prevalence & Season
Amatoxin species (Amanita bisporigera, A. phalloides, Galerina marginata) are the highest-priority clinical concern across the entire Midwest. A. bisporigera (Destroying Angel) is native throughout the region and is among the most common causes of serious mushroom poisoning. A. phalloides (Death Cap) is an introduced European species expanding its range in the Midwest via imported ornamental nursery trees (particularly oaks). Galerina marginata is present year-round on decaying wood. Primary season for all three: late summer through early fall (August–October).
False Morel (Gyromitra esculenta) is a spring species and is the highest-risk species during morel season (April–May), particularly in the upper Midwest and Great Lakes states. Experienced morel hunters who encounter it may not recognize it as a different species.
Cortinarius rubellus (Deadly Webcap) is present across the upper Midwest and Great Lakes region, particularly in boreal-influenced forests of Minnesota, Wisconsin, and Michigan. Its extreme toxicity latency (2–3 weeks) means cases frequently present as unexplained acute kidney injury; a mushroom history of 3–4 weeks prior must always be elicited.
Jack-o-Lantern (Omphalotus illudens) is among the most commonly ingested toxic mushrooms in the Midwest due to its confusion with chanterelles. It is abundant throughout the region in late summer and fall. Poison control centers should anticipate increased call volume August through October following wet periods that trigger large flushes.
Population note: Immigrant communities, particularly those from Southeast Asia and Eastern Europe where foraging is culturally common, may be at higher risk due to visual similarity between Midwest toxic species and edible species from their countries of origin. Translation services and culturally informed patient education are part of clinical management.