Clinical Use Only. This reference is intended for healthcare providers, poison control specialists, and trained foragers. It is not a foraging identification guide. Always contact Poison Control (1-800-222-1222) for real-time case management guidance. Treatment recommendations should be confirmed against current clinical guidelines.
Regional Scope: This guide covers the Pacific Northwest — Washington, Oregon, and Northern California. The region's temperate rainforest climate, diverse conifer forests, and oak woodlands support exceptionally high mushroom diversity, including several of North America's most dangerous species. Peak poisoning season runs fall through early spring.
Quick Reference — All 14 Species
| Common Name | Scientific Name | Tier | Toxin | Onset | Primary Risk |
|---|---|---|---|---|---|
| Death Cap | Amanita phalloides | Tier 1 | Amatoxins | 6–24 hr | Fulminant hepatic failure |
| Destroying Angel | Amanita ocreata | Tier 1 | Amatoxins | 6–24 hr | Fulminant hepatic failure |
| Deadly Galerina | Galerina marginata | Tier 1 | Amatoxins | 6–24 hr | Hepatic failure (even small doses) |
| Deadly Dapperling | Pholiotina rugosa | Tier 1 | Amatoxins (α-amanitin) | 6–24 hr | Amatoxin hepatorenal failure — lawn/mulch habitat, pediatric risk |
| Deadly Webcap | Cortinarius rubellus | Tier 1 | Orellanine | 2–3 weeks | Irreversible renal failure |
| Panther Cap | Amanita pantherina | Tier 2 | Ibotenic acid / Muscimol | 30 min – 2 hr | CNS toxidrome, seizures |
| Fly Agaric | Amanita muscaria | Tier 2 | Ibotenic acid / Muscimol | 30 min – 2 hr | Delirium, ataxia, sedation |
| Western Jack-o-Lantern | Omphalotus olivascens | Tier 2 | Illudin S | 1–3 hr | Severe GI — rarely fatal |
| False Parasol | Chlorophyllum molybdites | Tier 2 | Uncharacterized peptides | 1–3 hr | Profuse GI — rarely fatal |
| False Morel | Gyromitra esculenta | Tier 2 | Gyromitrin (MMH) | 2–24 hr | GI, hemolysis, methemoglobinemia, seizures — spring risk |
| Wavy Cap | Psilocybe cyanescens | Tier 3 | Psilocybin / Psilocin | 20–60 min | Hallucinogenic; panic, serotonin risk |
| Sweating Mushroom | Clitocybe dealbata | Tier 3 | Muscarine | 15–30 min | Cholinergic SLUDGE syndrome |
| Yellow-staining Mushroom | Agaricus xanthodermus | Tier 3 | Phenol derivatives | 30 min – 2 hr | GI upset — rarely serious |
| The Sickener | Russula emetica | Tier 3 | Sesquiterpenes | 30 min – 2 hr | GI upset — self-limiting |
Tier 1 — Life-Threatening
Potentially Fatal Species
These five species are responsible for the overwhelming majority of fatal mushroom poisonings in North America. Ingestion of even small amounts can cause irreversible organ failure. Any suspected exposure requires immediate emergency evaluation and Poison Control contact. Do not wait for symptoms to develop.
Death Cap
Amanita phalloides
Tier 1 — Life-Threatening
6–24 hr (GI); 48–96 hr (organ failure) ⚠
Identification Features
Cap: 5–15 cm, pale greenish-yellow to olive, smooth. Gills: Free, white, crowded — never green. Stem: White with a pendulous ring (annulus) and a cup-like volva sac at the base. Spore print: White. Habitat: Introduced species; mycorrhizal with planted oaks, chestnuts, and imported ornamentals. Common in urban parks, gardens, and suburbs of Seattle, Portland, and the Bay Area. Found year-round but peak fall–winter.
Toxic Compound(s)
Amatoxins (α-amanitin, β-amanitin, γ-amanitin); phallotoxins; virotoxins.
Onset Time
6–24 hr (GI); 48–96 hr (organ failure)
Mechanism of Toxicity
α-Amanitin inhibits RNA polymerase II, halting mRNA synthesis in hepatocytes and renal tubular cells. Phallotoxins disrupt the actin cytoskeleton. Result: progressive cell death over 3–7 days leading to fulminant hepatic and renal failure.
Clinical Symptoms
Phase 1 (6–24 hr): Watery diarrhea, nausea, vomiting, abdominal cramping. Phase 2 (24–48 hr): Apparent clinical improvement — do NOT discharge; LFTs begin rising. Phase 3 (48–96 hr): Fulminant hepatic failure, coagulopathy (rising INR), encephalopathy, acute kidney injury. Liver transplant criteria may be met by day 3–4.
Treatment Notes
Activated charcoal if <2 hr post-ingestion. Aggressive IV fluids. Serial LFTs, INR, creatinine every 6 hr. Antidotes: Silibinin IV (contact Poison Control for investigational access); high-dose IV penicillin G (competes for hepatocyte uptake). N-acetylcysteine as hepatoprotective adjunct. Early liver transplant evaluation — contact regional transplant center at first sign of rising INR. Urinary amatoxin ELISA if available.
⚠ Look-Alike Warning: Death Cap button stages are routinely mistaken for edible paddy straw mushrooms (Volvariella volvacea), especially in Asian-Pacific immigrant communities — the pattern behind most documented PNW fatalities. Both have a volva sac. Key differentiators: Death Cap has a greenish cap, persistent ring on stalk, and pure white gills. Also confused with young puffballs — always cut through the base to look for the volva.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Destroying Angel
Amanita ocreata
Tier 1 — Life-Threatening
6–24 hr (GI); 48–96 hr (organ failure) ⚠
Identification Features
Cap: 5–12 cm, pure white to ivory, smooth. Gills: Free, white, crowded. Stem: White, with a fragile ring and a prominent basal volva. Spore print: White. Habitat: Spring-fruiting (Feb–May); mycorrhizal with oaks, madrone, and manzanita. Common in coastal California oak woodlands extending into southern Oregon. Frequently found in suburban areas near established oaks.
Toxic Compound(s)
Amatoxins (α-amanitin, β-amanitin); phallotoxins.
Onset Time
6–24 hr (GI); 48–96 hr (organ failure)
Mechanism of Toxicity
Identical to A. phalloides: α-amanitin inhibits RNA polymerase II → progressive hepatocyte and renal tubular necrosis. Spring-fruiting window means peak risk occurs before most foragers are seasonally alert.
Clinical Symptoms
Phase 1 (6–24 hr): Severe cramping, nausea, vomiting, profuse watery diarrhea — often with significant dehydration. Phase 2 (24–48 hr): Symptomatic improvement with rising transaminases — the deceptive recovery window. Phase 3 (48–96 hr): Fulminant hepatic failure, coagulopathy, encephalopathy, AKI. High mortality without liver transplant.
Treatment Notes
Do NOT wait for Phase 3 deterioration. Activated charcoal if <2 hr. Aggressive IV hydration, serial labs (AST/ALT, INR, creatinine) every 6 hr. Silibinin IV (contact Poison Control). High-dose IV penicillin G. N-acetylcysteine. Early liver transplant evaluation — King's College criteria. All spring-season white Amanita ingestions must be treated as potential amatoxin poisoning.
⚠ Look-Alike Warning: Nearly identical to cultivated white button mushrooms (Agaricus bisporus) and field mushrooms (Agaricus campestris). Critical differentiator: Agaricus gills turn pink then brown at maturity; A. ocreata gills are always white. The basal volva is the key field mark — always dig up the base before eating any white mushroom.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Deadly Galerina
Galerina marginata
Tier 1 — Life-Threatening
6–24 hr (GI); 48–96 hr (organ failure) ⚠
Identification Features
Cap: 1–4 cm, honey-brown to tan, smooth, hygrophanous (fades as it dries). Gills: Attached, rusty-brown. Stem: Slender, 3–8 cm, with a fragile fibrous ring that often wears away. Spore print: Rusty-brown (critical). Habitat: Clusters on decaying conifer and hardwood logs and stumps. Extremely common throughout PNW forests year-round — one of the most abundant wood-inhabiting mushrooms in the region.
Toxic Compound(s)
Amatoxins (α-amanitin) — same compounds as Death Cap, potentially lethal even from a single cap.
Onset Time
6–24 hr (GI); 48–96 hr (organ failure)
Mechanism of Toxicity
α-Amanitin inhibits RNA polymerase II. A single small cap can contain sufficient amatoxin to cause fatal hepatotoxicity. Especially dangerous because of small size — multiple caps may be casually consumed.
Clinical Symptoms
Clinically indistinguishable from Amanita amatoxin poisoning: Phase 1 GI (6–24 hr) → Phase 2 apparent recovery → Phase 3 fulminant hepatorenal failure. Any wood-inhabiting mushroom ingestion with GI symptoms beginning >6 hr post-ingestion must trigger amatoxin workup.
Treatment Notes
Identical to Amanita phalloides protocol. Activated charcoal if <2 hr. Serial LFTs, INR, creatinine every 6 hr. Silibinin IV (contact Poison Control). High-dose IV penicillin G. N-acetylcysteine. Early liver transplant evaluation. Wood-habitat mushroom ingestion with delayed GI onset = amatoxin poisoning until proven otherwise.
⚠ Look-Alike Warning: Most commonly confused with Pholiota spp. and edible honey mushrooms (Armillaria spp.) — all are wood-inhabiting and brown. Critical differentiator: Galerina marginata has a rusty-brown spore print; honey mushrooms have a white spore print. Also mistaken for "magic mushrooms" (Psilocybe spp.) by recreational users — a potentially fatal error. Spore print is mandatory before consuming any small brown mushroom.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Deadly Webcap
Cortinarius rubellus
Tier 1 — Life-Threatening
2–3 weeks (renal symptoms); initial GI may occur within hours ⚠
Identification Features
Cap: 3–8 cm, reddish-brown to tawny, conical to broadly umbonate, dry and silky. Gills: Adnate, rusty-brown, covered when young by a cobweb-like cortina (partial veil) that leaves faint rusty staining on stalk. Stem: Club-shaped, same color as cap. Spore print: Rusty-brown. Habitat: Mycorrhizal with conifers — particularly spruce and fir — in moist mountain forests. Found throughout Cascades and Coast Ranges of WA and OR.
Toxic Compound(s)
Orellanine (bipyridyl N-oxide) — one of the most delayed-acting mushroom toxins known.
Onset Time
2–3 weeks (renal symptoms); initial GI may occur within hours
Mechanism of Toxicity
Orellanine generates free radicals that cause selective destruction of proximal tubular cells and glomerular capillaries. Mechanism is poorly understood but results in progressive, irreversible renal fibrosis. No antidote exists.
Clinical Symptoms
Latent phase (2–3 weeks): No symptoms during initial delay — patients may not recall the ingestion. Early (2–3 wk): Fatigue, headache, shivering, nausea, polydipsia. Late (3–6 wk): Oliguria progressing to anuria, flank pain, rising creatinine, proteinuria. Outcome: Permanent renal failure requiring dialysis or transplant in severe cases. The extreme delay between ingestion and symptoms makes clinical diagnosis challenging — always inquire about mushroom consumption in patients with unexplained acute kidney injury.
Treatment Notes
No specific antidote. Activated charcoal only useful if ingestion very recent (<2 hr). Supportive care: aggressive IV hydration, nephrology consultation, serial renal function monitoring. N-acetylcysteine has been used empirically. Hemodialysis for severe AKI. Renal transplant in cases of irreversible failure. Contact Poison Control for current management guidance — orellanine poisoning is rare and management is evolving.
⚠ Look-Alike Warning: Numerous edible Cortinarius species share a similar appearance; the genus is notoriously difficult to identify. Also confused with edible chanterelles and other tawny woodland mushrooms by inexperienced foragers. The cobweb-like cortina is characteristic of Cortinarius but may be absent in older specimens. Key clinical clue: unexplained AKI 2–4 weeks after forest mushroom consumption anywhere in the Pacific Northwest.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Deadly Dapperling
Pholiotina rugosa
Tier 1 — Life-Threatening
6–24 hr (GI); 48–96 hr (organ failure) ⚠
Identification Features
Cap: 1–3 cm, honey-brown to cinnamon, convex. Gills: Rusty-cinnamon-brown (from spore deposit). Stem: Slender with a fragile membranous ring that may wear away. Spore print: Rusty-cinnamon-brown. Habitat: Lawns, wood-chip mulch, garden beds, and disturbed soil throughout the PNW — extremely common in suburban gardens and parks in Seattle, Portland, and coastal cities. Also known as Conocybe filaris.
Toxic Compound(s)
Amatoxins (α-amanitin, β-amanitin) — same compounds as Death Cap. Concentration per gram rivals Amanita species despite the small mushroom size.
Onset Time
6–24 hr (GI); 48–96 hr (organ failure)
Mechanism of Toxicity
α-Amanitin inhibits RNA polymerase II → progressive hepatocellular necrosis. A child ingesting several small mushrooms from garden mulch can receive a potentially fatal dose.
Clinical Symptoms
Phase 1 (6–24 hr): Nausea, vomiting, abdominal pain, diarrhea. Phase 2 (24–48 hr): Apparent improvement — do NOT discharge. Phase 3 (48–96 hr): Fulminant hepatic failure, rising transaminases, coagulopathy, AKI.
Treatment Notes
Full amatoxin protocol: activated charcoal if <2 hr and airway protected; aggressive IV hydration; serial LFTs, INR, creatinine q6h; hepatology consult; silibinin IV (contact Poison Control); early liver transplant evaluation. Pediatric lawn ingestion: Any child with GI symptoms >6 hr after outdoor play where small mushrooms were accessible must be evaluated for amatoxin poisoning — do not dismiss as a benign exposure.
⚠ Look-Alike Warning: Resembles edible Agrocybe species and Marasmius oreades (Fairy Ring Mushroom — both common in lawns). Critical differentiator: Marasmius oreades has widely-spaced, non-fragile gills and NO ring. Pholiotina rugosa has close, brown gills and a fragile ring. Also mimics Galerina marginata (same rusty-brown spore print, both potentially amatoxin-containing). Any brown ringed mushroom from lawn or mulch in the PNW should be treated as potentially amatoxin-containing.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Tier 2 — Serious
Serious / Potentially Severe Species
These species cause significant toxicity and may require hospitalization, particularly in children, the elderly, or patients with comorbidities. While fatalities are uncommon with appropriate care, severe cases can be life-threatening. All require prompt Poison Control contact.
Panther Cap
Amanita pantherina
Tier 2 — Serious
30 min – 2 hr
Identification Features
Cap: 5–12 cm, brown to grayish-brown, with white wart-like patches (veil remnants). Gills: Free, white. Stem: White with a hanging ring and a basal bulb with a collar (not a free-rimmed volva). Spore print: White. Habitat: Mycorrhizal with conifers and mixed forests throughout PNW — extremely common, one of the most frequently reported toxic species in the region.
Toxic Compound(s)
Ibotenic acid and muscimol (GABA-A agonist / NMDA antagonist). Higher concentrations than A. muscaria. Trace muscarine.
Onset Time
30 min – 2 hr
Mechanism of Toxicity
Muscimol (decarboxylation product of ibotenic acid) is a potent GABA-A agonist causing sedation and delirium. Ibotenic acid is an excitatory NMDA agonist causing agitation. Combined effect: a mixed excitatory-sedative toxidrome. Panther Cap has significantly higher toxin concentrations than Fly Agaric.
Clinical Symptoms
CNS: Confusion, agitation, delirium, visual hallucinations, ataxia, myoclonus. Sedation phase: Hypersomnia, potential respiratory depression at high doses. Autonomic: Dry mouth, mydriasis, urinary retention. Severe (esp. children): Seizures, coma. Pediatric fatalities documented. PNW has higher incidence of Panther Cap poisoning than most US regions.
Treatment Notes
Secure airway — respiratory depression risk is real. Do NOT administer physostigmine. Benzodiazepines for agitation or seizures. Close monitoring of respiratory rate and O₂ saturation. Most symptoms resolve within 6–8 hr with supportive care. Activated charcoal if alert and within 1 hr. This species is significantly more dangerous than Fly Agaric — contact Poison Control for all exposures.
⚠ Look-Alike Warning: Confused with edible Amanita rubescens (The Blusher) — differentiator: Blusher flesh turns pink/red when cut; Panther Cap does not. Also confused with Fly Agaric (A. muscaria) — Fly Agaric typically has a red/orange cap. Confused with various edible brown-capped fungi by inexperienced foragers.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Fly Agaric
Amanita muscaria
Tier 2 — Serious
30 min – 2 hr
Identification Features
Cap: 8–20 cm, vivid red to orange-red (occasionally yellow in var. guessowii), covered with white wart-like patches. Gills: Free, white, crowded. Stem: White, with a prominent skirt-like ring and a basal bulb with concentric rings. Spore print: White. Habitat: Mycorrhizal with birch, pine, and spruce. Common throughout PNW — iconic and highly recognizable.
Toxic Compound(s)
Ibotenic acid and muscimol. Trace amounts of muscarine. Lower concentration than A. pantherina.
Onset Time
30 min – 2 hr
Mechanism of Toxicity
Muscimol (GABA-A agonist): sedation, delirium, ataxia. Ibotenic acid (NMDA agonist): agitation, excitation. The balance of excitatory and sedative effects varies with dose and specimen. Sometimes intentionally consumed for psychoactive effects — patients may downplay exposure.
Clinical Symptoms
Delirium, confusion, visual disturbances, ataxia, alternating agitation and somnolence. Autonomic signs mild: salivation, nausea, occasionally vomiting. Respiratory depression rare at typical doses. Children more susceptible. Symptoms self-limiting in most adults within 6–8 hr.
Treatment Notes
Primarily supportive. Protect airway. Quiet, low-stimulation environment. Benzodiazepines for severe agitation. Monitor vital signs. Symptoms typically resolve within 4–8 hr. Activated charcoal if within 1 hr and patient is alert and cooperative. Note: some patients intentionally ingest this species — obtain accurate history without judgment.
⚠ Look-Alike Warning: The red cap with white warts is distinctive, but warts can wash off in rain, leaving it resembling a plain red cap. Yellow variants (A. muscaria var. guessowii) may be confused with edible chanterelles or other yellow-capped fungi. The white-gilled, ring-bearing, bulbous base distinguishes it from chanterelles (no true gills, no ring, no bulb).
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Western Jack-o-Lantern
Omphalotus olivascens
Tier 2 — Serious
1–3 hr
Identification Features
Cap: 5–20 cm, bright orange to olive-orange, convex to vase-shaped, smooth. Gills: Decurrent (running down stalk), deep orange, sharp and blade-like — bioluminescent in darkness. Stem: Orange, often off-center, solid. Spore print: White to cream. Habitat: Grows in dense clusters at the base of oaks, eucalyptus, and buried wood/roots. Common in coastal California and southern Oregon. Fall fruiting.
Toxic Compound(s)
Illudin S (sesquiterpene) — a cytotoxic compound. Possibly other terpenoids.
Onset Time
1–3 hr
Mechanism of Toxicity
Illudin S disrupts DNA repair mechanisms and inhibits RNA/DNA synthesis. Primary effect is severe gastrointestinal irritation via direct mucosal damage. Not typically fatal in adults but can cause dangerous dehydration.
Clinical Symptoms
Severe nausea, vomiting (often intractable), watery diarrhea, and abdominal cramping beginning 1–3 hr post-ingestion. Symptoms may be prolonged (up to 24 hr). Rarely causes cardiac arrhythmias or neurological symptoms at high doses. Dehydration and electrolyte imbalance are the primary clinical concerns.
Treatment Notes
Aggressive IV fluid and electrolyte replacement. Antiemetics. Cardiac monitoring if large quantity consumed. Most patients recover within 24–48 hr with supportive care. Activated charcoal if within 1 hr and patient is not vomiting.
⚠ Look-Alike Warning: Most commonly confused with golden chanterelles (Cantharellus californicus, C. cibarius) — one of the most common misidentifications in California and Oregon. Critical differentiators: Jack-o-Lantern has true sharp gills (chanterelles have blunt forking ridges), grows in dense clusters from wood (chanterelles grow singly from soil), and smells unpleasant (chanterelles have a fruity/apricot aroma). Bioluminescence of gills visible in darkness is definitive.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
False Parasol
Chlorophyllum molybdites
Tier 2 — Serious
1–3 hr
Identification Features
Cap: 10–30 cm, white to buff, with shaggy brown scales. Gills: Free, white in youth turning greenish-gray at maturity. Stem: White, smooth, with a prominent double ring. Spore print: Green (diagnostic). Habitat: Lawn and grassland mushroom — found in urban and suburban lawns, parks, and golf courses. More common in warmer regions but found increasingly in coastal California and OR urban areas. Often forms fairy rings.
Toxic Compound(s)
Uncharacterized peptides and glycoproteins — mechanism not fully elucidated.
Onset Time
1–3 hr
Mechanism of Toxicity
Direct gastrointestinal irritant. May have some immunological component. Not hepatotoxic. One of the most common causes of mushroom GI poisoning in North America due to its lawn habitat and large size.
Clinical Symptoms
Rapid-onset nausea, profuse vomiting, watery diarrhea, and severe cramping within 1–3 hr. Symptoms can be extremely distressing and prolonged (up to 8–10 hr). Dehydration risk, especially in children and elderly. Rarely, transient neurological symptoms reported.
Treatment Notes
Supportive care: IV fluids, antiemetics, electrolyte replacement. Generally self-limiting within 12–24 hr. Activated charcoal if within 1 hr. Most patients do not require hospitalization unless dehydration is severe.
⚠ Look-Alike Warning: Resembles edible parasol mushrooms (Macrolepiota procera) and edible shaggy mane (Coprinus comatus). Critical differentiator: green spore print is diagnostic — no edible species has a green spore print. Also: mature False Parasol gills turn distinctly greenish. Edible parasol mushrooms have white spore prints and grow in forest edges, not lawns.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
False Morel
Gyromitra esculenta
Tier 2 — Serious
2–24 hr post-ingestion
Identification Features
Cap: 3–15 cm, reddish-brown to dark brown, irregularly brain-like or saddle-shaped, with convoluted wrinkled lobes — NOT a regular honeycomb of pits and ridges. Stem: White to pale, stout, irregular, often ribbed or furrowed, chambered internally. Habitat: Spring-fruiting. Found in sandy soils under conifers (pines, firs) and along forest edges throughout the PNW — common in the Cascades and Coast Ranges from March to June. Peak confusion season coincides with true morel season.
Toxic Compound(s)
Gyromitrin — a hydrazine compound that hydrolyzes to monomethylhydrazine (MMH), a volatile hepatotoxin and CNS poison also used in rocket fuel.
Onset Time
2–24 hr post-ingestion
Mechanism of Toxicity
MMH causes oxidative hemolysis, inhibits pyridoxal phosphate (Vitamin B6) metabolism (similar to isoniazid toxicity), and is directly hepatotoxic. Volatile — some MMH may be lost with thorough cooking or drying, but this is unreliable. Inhalation of cooking vapors can cause toxicity in bystanders.
Clinical Symptoms
GI (2–24 hr): Nausea, vomiting, watery diarrhea, abdominal cramps, weakness. CNS (severe cases): Headache, dizziness, ataxia. Hemolytic (24–72 hr): Hemolysis, methemoglobinemia (cyanosis, dyspnea). Hepatic: Rising AST/ALT/bilirubin; jaundice. Seizures in severe cases. Fatalities documented in Europe; rare in North America.
Treatment Notes
Pyridoxine (Vitamin B6) — 25 mg/kg IV as antidote for seizures and CNS symptoms (competes with MMH for B6-dependent enzymes). Methylene blue (1–2 mg/kg IV) for methemoglobinemia. Activated charcoal if within 2 hr. IV fluids, antiemetics. Serial LFTs, CBC with differential, methemoglobin levels. Hepatology consultation for significant hepatotoxicity. Avoid patient eating any Gyromitra-suspected mushroom.
⚠ Look-Alike Warning: Most dangerous confusion: True Morels (Morchella spp.) — both are spring-fruiting fungi with cap-stalk morphology found in PNW conifer forests. True morels have a regular honeycomb of pits and ridges covering the entire cap; Gyromitra has irregular wrinkled brain-like lobes. Both can be hollow when cut. Any patient presenting with GI illness in spring after eating foraged 'morels' must be considered for Gyromitra poisoning — perform liver function tests.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Tier 3 — Moderate
Moderate / Situationally Serious Species
These species generally cause non-fatal poisonings in healthy adults, but can be clinically significant in pediatric patients, the elderly, or those on certain medications. Severity varies with dose. Poison Control consultation recommended for all symptomatic ingestions.
Wavy Cap
Psilocybe cyanescens
Tier 3 — Moderate
20–60 min
Identification Features
Cap: 2–5 cm, chestnut-brown when moist, fading to pale yellow/cream as it dries, with a distinctively undulating (wavy) margin. Gills: Adnate to adnexed, initially pale gray, darkening to purplish-brown with age. Bluing reaction when bruised. Stem: 4–8 cm, whitish, fibrous, bruises blue. Spore print: Dark purple-brown. Habitat: Wood chips, mulched garden beds, path edges — common in PNW urban areas; one of the most potent psilocybin mushrooms in the world and highly prevalent in the Pacific Northwest.
Toxic Compound(s)
Psilocybin (prodrug) and psilocin (active compound); baeocystin.
Onset Time
20–60 min
Mechanism of Toxicity
Psilocin is a serotonin 5-HT2A receptor agonist. Produces dose-dependent hallucinogenic, perceptual, and mood effects. Serotonin syndrome risk if combined with serotonergic medications (SSRIs, MAOIs, SNRIs, triptans). High doses may cause dangerous panic, dissociation, or self-harm.
Clinical Symptoms
Visual and auditory hallucinations, altered time perception, emotional lability, anxiety, panic attacks. Physiological: mydriasis, tachycardia, mild hypertension, tremor, nausea. Severe: Serotonin syndrome (with drug interactions), hyperthermia, rhabdomyolysis, psychosis. Wavy Cap has significantly higher psilocin content than most other Psilocybe species.
Treatment Notes
Quiet, low-stimulation environment; calm reassurance ('talk-down'). Benzodiazepines for severe anxiety or agitation. For serotonin syndrome: discontinue any serotonergic agents, supportive cooling, cyproheptadine if indicated — contact Poison Control. Antipsychotics (haloperidol) for prolonged psychosis. Monitor for hyperthermia. Check for co-ingestion of other substances. Legal context: Psilocybe possession is decriminalized in some Oregon municipalities but remains federally controlled.
⚠ Look-Alike Warning: Commonly mistaken for Galerina marginata (Deadly Galerina) — a potentially fatal error. Both are small brown mushrooms on wood chips. Critical differentiator: Psilocybe cyanescens exhibits a strong bluing reaction when bruised (psilocin oxidation); Galerina marginata does not blue. However, bluing can be subtle — spore print is critical: Psilocybe = dark purple-brown; Galerina = rusty-brown. Do not rely on bluing alone.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Sweating Mushroom
Clitocybe dealbata
Tier 3 — Moderate
15–30 min
Identification Features
Cap: 2–5 cm, white to off-white, convex to flat or slightly funnel-shaped, dry, often with a wavy margin. Gills: Decurrent (running down stalk), crowded, white to cream. Stem: Short, white, brittle. Spore print: White. Habitat: Grassy areas, lawns, meadows — often grows in fairy rings. Common throughout PNW in autumn.
Toxic Compound(s)
Muscarine (high concentration — up to 10× higher than Fly Agaric).
Onset Time
15–30 min
Mechanism of Toxicity
Muscarine is a direct muscarinic acetylcholine receptor agonist. Activates M2 (cardiac) and M3 (exocrine/smooth muscle) receptors, producing the classic cholinergic SLUDGE toxidrome. Does not cross the blood-brain barrier significantly — primarily peripheral effects.
Clinical Symptoms
SLUDGE syndrome: Salivation, Lacrimation, Urination, Defecation, GI distress (nausea/vomiting/cramping), Emesis. Also: miosis, bradycardia, bronchospasm, diaphoresis. Onset is rapid. Severe cases: respiratory failure from bronchospasm and excess secretions. Rarely fatal in healthy adults but dangerous in children and elderly.
Treatment Notes
Atropine is the antidote — titrate to drying of secretions (not heart rate). Start at 0.5–2 mg IV; repeat every 5–10 min as needed. Glycopyrrolate as alternative. Bronchodilators for bronchospasm. Airway management for excessive secretions. Contact Poison Control — atropine dosing guidance is critical.
⚠ Look-Alike Warning: Commonly confused with fairy ring mushrooms (Marasmius oreades) — both grow in rings in grassy areas. Critical differentiator: Fairy ring mushroom has widely spaced gills that do NOT run down the stalk, and a tough wiry stalk that bends without breaking. C. dealbata has crowded decurrent gills and a brittle stalk.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Yellow-staining Mushroom
Agaricus xanthodermus
Tier 3 — Moderate
30 min – 2 hr
Identification Features
Cap: 5–15 cm, white, smooth, convex to flat. Gills: Free, initially pink, turning chocolate-brown at maturity. Stem: White with a pendant ring; base stains bright chrome-yellow when cut or rubbed (diagnostic). Odor: Unpleasant phenolic/chemical smell, especially at stem base. Spore print: Dark brown. Habitat: Lawns, gardens, roadsides, woodland edges throughout PNW.
Toxic Compound(s)
Phenol derivatives (primarily phenol and p-cresol). Mechanism not fully characterized.
Onset Time
30 min – 2 hr
Mechanism of Toxicity
Phenolic compounds cause direct gastrointestinal irritation. Some individuals appear to have hypersensitivity reactions; the majority who consume this species in small amounts may have minimal symptoms. Raw consumption worsens symptoms.
Clinical Symptoms
Nausea, cramping, vomiting, and diarrhea typically beginning 30 min – 2 hr after ingestion. Symptoms are usually mild to moderate and self-limiting within a few hours. Some individuals (particularly those with phenol sensitivities) may have more severe reactions including diaphoresis and tachycardia. Generally not life-threatening in healthy adults.
Treatment Notes
Supportive care: antiemetics, oral or IV hydration as needed. Most cases resolve within 4–6 hr without intervention. Activated charcoal rarely needed. Contact Poison Control if symptoms are severe or patient is a child or elderly.
⚠ Look-Alike Warning: Closely resembles edible Agaricus species including A. campestris (field mushroom) and A. bisporus (button mushroom). The yellow-staining reaction at the base and the phenolic odor are the key differentiators — edible Agaricus species do NOT stain chrome-yellow and have a pleasant mushroom smell. Also superficially resembles Death Cap buttons — always check for yellow staining and examine gills (white gills + no staining = potential Amanita).
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
The Sickener
Russula emetica
Tier 3 — Moderate
30 min – 2 hr
Identification Features
Cap: 4–10 cm, vivid scarlet-red, often fading at center, smooth, sticky when moist, cuticle peels easily from margin. Gills: Adnate, white, brittle. Stem: White, brittle, crumbles easily. Taste: Very acrid/peppery (diagnostic). Spore print: White. Habitat: Mycorrhizal with conifers — spruce, fir, pine. Common in moist PNW conifer forests in autumn. Russula spp. are notoriously difficult to identify at the species level.
Toxic Compound(s)
Sesquiterpene compounds (sescoterpenes); exact emetic agents poorly characterized.
Onset Time
30 min – 2 hr
Mechanism of Toxicity
Direct gastrointestinal irritation. Heat-stable toxins (symptoms persist even after cooking, though reduced). The acrid taste normally prevents large quantity ingestion. Mechanism of emetic action not fully elucidated.
Clinical Symptoms
Nausea, vomiting, and diarrhea typically within 30 min – 2 hr. Generally self-limiting within 4–6 hr. Rarely causes serious complications in healthy adults. Children may be more severely affected due to relative dose. Prolonged severe GI symptoms beyond 6 hr should prompt consideration of alternative diagnoses (amatoxin, orellanine).
Treatment Notes
Supportive care: hydration, antiemetics. Symptoms are self-limiting. Monitor for dehydration in children. Contact Poison Control if symptoms persist beyond 6 hr, as prolonged symptoms may indicate co-ingestion with a more toxic species. Important: Russula taxonomy is complex — species confirmation by an expert mycologist is advisable when clinically relevant.
⚠ Look-Alike Warning: The red cap may be confused with edible red-capped species. However, the brittle texture, easily-peeling cap skin, and intensely acrid taste are characteristic of Russula. More importantly, the vivid red color may cause confusion with edible red-capped chanterelles or other mushrooms. Key: Russula gills are white and very brittle; chanterelles have forking blunt ridges, not true gills.
☎ Poison Control: 1-800-222-1222 — call immediately for case management guidance
Pacific Northwest Clinical Notes
The Pacific Northwest presents a unique clinical profile. Amatoxin poisoning (Death Cap, Destroying Angel, Deadly Galerina) accounts for the majority of serious and fatal cases — the region's dense urban tree canopy with planted oaks and chestnuts places Death Cap in suburban neighborhoods. Orellanine nephrotoxicity (Cortinarius spp.) is clinically important because of the extreme symptom delay — always inquire about mushroom ingestion in unexplained AKI cases. Panther Cap poisoning is disproportionately common in the PNW relative to other US regions. Wavy Cap (Psilocybe cyanescens) is one of the world's most potent psilocybin-containing mushrooms and is abundant in PNW urban wood-chip mulch — emergency presentations for anxiety, psychosis, and serotonin syndrome are increasing. The chanterelle season (August–November) drives a predictable peak in Western Jack-o-Lantern misidentification. Poison Control resources: 1-800-222-1222 (national) or Oregon Poison Center (OHSU): 1-800-222-3320.
Look-Alike Comparison Table
The most dangerous field identification errors in the Pacific Northwest — toxic species confused with edible or non-toxic ones.
| Toxic Species | Commonly Confused With | Key Differentiators | Risk Level |
|---|---|---|---|
| Death Cap A. phalloides |
Paddy Straw Mushroom Volvariella volvacea |
Death Cap: greenish cap, ring on stalk, white gills, volva sac. Paddy Straw: no ring, pink gills at maturity. Both share a volva — always check gill color. | Lethal |
| Destroying Angel A. ocreata |
White Button Mushroom Agaricus bisporus |
Destroying Angel: white gills at all stages, prominent volva sac at base. Button mushroom: gills turn pink then brown, no volva, no woodland habitat. | Lethal |
| Deadly Galerina G. marginata |
Honey Mushroom Armillaria spp. |
Galerina: rusty-brown spore print, smaller, on conifer wood. Honey Mushroom: white spore print, often larger, frequently on hardwood. A spore print is mandatory. | Lethal |
| Deadly Galerina G. marginata |
Wavy Cap Psilocybe cyanescens |
Psilocybe: bluing when bruised, dark purple-brown spore print. Galerina: no bluing, rusty-brown spore print. Confusing these is potentially fatal. | Lethal |
| Western Jack-o-Lantern O. olivascens |
Golden Chanterelle Cantharellus californicus |
Jack-o-Lantern: true sharp gills, clusters from wood/roots, unpleasant smell, bioluminescent. Chanterelle: blunt forking ridges (not true gills), grows singly from soil, fruity aroma. | Serious |
| False Parasol C. molybdites |
Parasol Mushroom Macrolepiota procera |
False Parasol: green spore print, gills turn greenish, lawn habitat. Edible Parasol: white spore print, white gills, woodland edges. Green spore print = definitive ID. | Serious |
| Panther Cap A. pantherina |
Blusher Amanita rubescens |
Panther Cap: flesh does NOT change color when cut. Blusher: flesh turns pink to red when cut or bruised. Careful observation required — this is a critical but subtle distinction. | Life-Threatening |
| Sweating Mushroom C. dealbata |
Fairy Ring Mushroom Marasmius oreades |
Sweating Mushroom: crowded decurrent gills, brittle stalk, grows in grass. Fairy Ring: widely spaced non-decurrent gills, tough wiry stalk that bends without breaking. | Serious |