Can you overdose on magic mushrooms? Toxicity, poison center data and warning signs

The short answer

A fatal poisoning from psilocybin mushrooms alone appears to be very rare. US poison centers logged no deaths among 1,510 single-substance hallucinogenic mushroom exposures in 2023 and 1,389 in 2024, though 30 and 29 of those cases had a major effect, the most severe outcome short of death.¹² In Australian coroners' records from 2000 to 2023, 4 of 10 psilocybin-related deaths were traumatic accidents, and psilocybin was the only drug found in 2.³ The danger is mostly what happens around it: accidents, other drugs, strain on the heart, and products that don't contain what the label says.

What the toxicity evidence says, and what it can't

A Dutch risk assessment rated psilocybin mushrooms' acute toxicity as moderate, and their chronic toxicity and dependence potential as low; its main concerns were panic attacks and flashbacks.⁴ In the 2017 Global Drug Survey, 19 of 9,233 people who had used magic mushrooms in the past year (0.2%) sought emergency treatment, mostly for anxiety, panic or paranoia, and all but one were back to normal within 24 hours.⁵

These numbers have limits: poison center records include only the cases someone reports, and the report notes that an exposure doesn't necessarily mean a poisoning or overdose.² And mushrooms vary widely in strength, as our potency data shows, so figures from any study say little about an unknown mushroom.

How psilocybin-related deaths happen

From 2000 to 2023, Australia's national coronial database recorded 10 psilocybin-related deaths, with a median age of 26. Traumatic accidents accounted for 40% and multiple drug toxicity for 20%, the cause was undetermined in 4 cases, and psilocybin was the only drug in 20%. Severe agitation was the most common presentation (20%).³

US fatality listings show the same mix. In 2024, psilocybin mushrooms appeared in 2 deaths, both of 19-year-old men and both with LSD ranked as the main substance;² in 2023, they appeared in 1 multi-substance death, ranked third.¹ Across 6,933 psilocybin-related poison center cases from 2013 to 2022, including those with other substances, 8 people died (0.1%).⁶ If you take prescription medicines, see our interaction checker.

US poison center counts, 2023 and 2024

Figures from Table 22A.¹² A separate code for processed psilocybin products, added on December 4, 2023, logged 185 case mentions in 2024 and 143 single-substance exposures, 33 of them in children 5 and under, with 5 major effects and no deaths.² Over the longer run, psilocybin-related poison center cases rose about threefold, from 477 in 2013 to 1,441 in 2022, mostly after 2019; 87% received care in a health care facility, and 10% of those were admitted to critical care.⁶

Exposures in young children are rising

From 2000 to 2024, poison centers logged 41,612 unintentional recreational drug ingestions in children under 6, and psilocybin mushrooms and products made up 1,131 (2.7%). Their rate rose from 0.06 per 100,000 children in 2018 to 0.94 in 2024, an increase of 1,466.7%. Compared with other substances, these ingestions were less likely to involve a major effect (RR 0.10; 95% CI 0.04 to 0.24) or a critical care admission (RR 0.25). The authors note that a reported ingestion doesn't necessarily mean a poisoning, and that processed "mushroom" products coded as psilocybin may inflate the count.⁷ From 2010 to 2024, 258 of 1,195 processed mushroom product exposures (21.6%) were in children under 13.²

If a child may have eaten any mushroom or mushroom product, call Poison Control at 1-800-222-1222 right away,⁸ and call 911 for any of the signs listed below.

Mislabeled products: the Diamond Shruumz outbreak

In 2024, chocolate bars, cones and gummies sold as "mushroom" products made people seriously ill. CDC's report of the investigation, published in MMWR on April 9, 2026, counted 180 cases in 34 states: 73 hospitalized, including 38 ICU admissions and 29 endotracheal intubations, and two deaths noted as associated with the outbreak.⁹ FDA's outbreak page carries the 2024 investigation count (as of October 31, 2024): 180 illnesses, of which 118 people reportedly ate a Diamond Shruumz product, 36 an unspecified-brand mushroom chocolate bar and 26 a non-Diamond Shruumz brand; 73 hospitalizations; and "three (3) potentially associated deaths".¹⁰ The 2026 report puts the deaths at two. Compared with other mushroom-containing chocolates, eating Diamond Shruumz bars was associated with higher odds of hospitalization (OR 3.29; 95% CI 1.51 to 7.40), ICU admission (OR 6.30), seizures (OR 8.45) and intubation (OR 8.04).⁹

FDA tested 22 chocolate bars, 10 cones and 22 gummies. It found muscimol in 9 bars and 5 cones; psilocin in 4 bars, 5 cones and 14 gummies; acetylpsilocin (4-AcO-DMT) in 9 bars, 5 cones and 14 gummies; pregabalin, a prescription drug, in 3 bars, 5 cones and 4 gummies; and kavalactones in 18 bars, all 10 cones and 11 gummies. Composition varied even within the same flavor.¹⁰ More broadly, in 362 psychoactive mushroom edible exposures in 2023 and 2024, taking more than one substance (aOR 2.58), confusion (aOR 3.06) and central nervous system depression (aOR 2.55) were each associated with hospital admission.¹¹

Warning signs that mean call 911

• Collapse, a seizure, trouble breathing, or someone who can't be woken. Poison Control's advice for these is "Call 911 now!"¹²
• Chest pain, especially crushing, squeezing or pressure, pain spreading to the jaw, left arm or between the shoulder blades, or chest pain with sweating, nausea, dizziness, a racing heart or shortness of breath.¹³
• Signs of serotonin toxicity, especially in someone on an antidepressant or an MAOI: muscle jerking or rigidity, a high fever, severe agitation or unresponsiveness, swinging heart rate or blood pressure, or seizures.¹⁴
• Severe agitation or behavior that could cause a fall or other injury. In the Australian records, 4 of 10 deaths were traumatic accidents.³
• Anyone who might hurt themselves. For thoughts of suicide without immediate danger, call or text 988.

For a frightening experience without these signs, the Fireside Project's peer support line takes calls and texts at 62-FIRESIDE (623-473-7433), every day from 11 a.m. to 11 p.m. Pacific. It isn't a suicide hotline or a medical service, and it directs emergencies to 911.¹⁵ Poison Control answers around the clock.⁸ Our help page covers what to do while you wait.

What to tell responders

• What was taken, roughly when, and the product name. Bring the package if there is one: the Diamond Shruumz products contained ingredients buyers didn't expect.¹⁰
• Everything else taken, including alcohol and cannabis. Taking more than one substance was linked to hospital admission.¹¹
• Every prescription medicine, especially lithium, antidepressants, MAOIs and stimulants.
• Any heart condition, seizure history or pregnancy (see who clinical trials exclude).