Fly Agaric Poisoning: Symptoms, Onset and What to Do

Fly agaric (Amanita muscaria) is poisonous. Symptoms usually start 30 minutes to 2 hours after eating it. They range from vomiting and confusion to seizures and coma. There is no antidote. If someone may have eaten it, call Poison Control (1-800-222-1222 in the US) or your local emergency number straight away.

This page replaces an older "benefits and safe use" post. It is not a how-to. It covers what poisoning looks like, how fast it starts, who is most at risk and what to do if it happens.

What does fly agaric poisoning look like?

Fly agaric contains two main active compounds. Ibotenic acid excites the nervous system. Muscimol depresses it. Because both act at once, symptoms can swing between agitation and heavy sedation (Michelot & Melendez-Howell, Mycological Research, 2003).

A 2025 review in Toxins describes a typical pattern (Stoeva-Grigorova et al., Toxins, 2025):

• Early stomach symptoms: nausea, vomiting, diarrhoea.
• Then nervous-system symptoms: confusion, dizziness, muscle jerks, and heightened sensitivity to light and sound.
• An excited phase with hallucinations, agitation and poor coordination.
• Then deep sleep, which can become coma.

The US Food and Drug Administration reviewed the literature in 2024. It lists seizures, coma, breathing depression and death among the reported outcomes in severe cases (FDA Scientific Memorandum on Amanita muscaria, September 2024). For a closer look at how these effects arrive in sequence, see our guide to the three pharmacologies behind fly agaric side effects.

How fast do symptoms start, and how long do they last?

Onset is fast. The FDA memorandum summarises the literature as symptoms within 30 minutes to 2 hours of eating the mushroom. The 2025 Toxins review gives a similar window of 30 minutes to 2–3 hours.

Most cases settle within about a day. But not all do. The FDA memorandum cites reports of delirium, hallucinations and paranoid psychosis lasting up to five days. It also cites a case of coma lasting 72 hours that needed a breathing tube.

Serious outcomes can be delayed. In one published case, a 44-year-old man had a cardiac arrest about 10 hours after eating 4 to 5 dried caps. He died nine days later (Meisel et al., Wilderness & Environmental Medicine, 2022). The same paper describes a 75-year-old man who ate one foraged cap by mistake. He needed a breathing tube but recovered.

Who is most at risk?

The published cases point to a few groups:

• Children and pets. The FDA memorandum cites child poisonings with coma and breathing arrest. It also cites dog poisonings, some of them fatal. In one report, the mushrooms were growing near where the dogs were kept.
• Older adults. The 2025 Toxins paper reports two spouses aged 78 and 79 poisoned after preparing the mushroom at home. Home preparation does not remove the danger: drying converts part of the ibotenic acid into muscimol, the compound the FDA names as the likely driver of major poisoning signs (Tsunoda et al., Journal of the Food Hygienic Society of Japan, 1993).
• Foragers. The same review names misidentification as the main cause of mushroom poisoning. Our article on why "red with white spots" is a poor identification rule explains why.
• People taking it on purpose. A 2025 report from Lithuania describes four men hospitalised in 2023 after intentional use. One needed a breathing tube after three dried mushrooms (Savickaitė & Laubner-Sakalauskienė, Acta Medica Lituanica, 2025).
• Buyers of edibles. After the 2024 recall of Diamond Shruumz products, the FDA had received 58 illness reports, including 30 hospitalisations, as of 9 July 2024. The maker named muscimol as the cause.

Anyone who has also taken alcohol, sleeping pills or other sedatives is a particular concern. Muscimol acts on the same GABA-A receptor system as those drugs, so their sedating effects can add up.

What to do if someone may have eaten fly agaric

Do not wait to see whether symptoms pass. Symptoms can start fast and serious ones can come hours later.

• Call for help now. In the US, call Poison Control on 1-800-222-1222 or use webPOISONCONTROL online. Elsewhere, call your national poison centre or local emergency number (112 across the EU, 999 in the UK).
• Call 911 or your emergency number at once if the person collapses, has a seizure, has trouble breathing or cannot be woken (Poison Control, National Capital Poison Center, accessed September 2026).
• Keep what is left. Save any remaining mushroom, packaging or a photo. In published cases, clinicians and mycologists used leftover specimens to confirm the species.
• For pets, call your vet or an emergency vet straight away.

There is no specific antidote. Hospital care is supportive: help with breathing and circulation, and medicines for seizures or agitation. The Toxins authors warn that atropine, sometimes assumed to help, only blocks some effects and must be used with care. That is a decision for clinicians, not for home treatment.

Frequently Asked Questions

Can fly agaric kill you?

Deaths are rare but documented. A 2022 case report describes a man who died after eating 4 to 5 dried caps (Meisel et al., 2022), and the FDA's 2024 review lists death among reported outcomes of severe poisoning.

How long after eating fly agaric do symptoms start?

Usually within 30 minutes to 2 hours, according to the FDA's 2024 literature review. Some serious effects, including cardiac arrest in one reported case, came many hours later.

Is there an antidote for fly agaric poisoning?

No. Treatment is supportive care in hospital, such as breathing support and medicines for seizures or agitation (Stoeva-Grigorova et al., 2025).

Does drying or boiling make fly agaric safe?

No. Drying converts part of the ibotenic acid into muscimol, which a 1993 study concluded would intensify toxicity (Tsunoda et al., 1993), and the FDA notes that toxic compounds were still measurable after boiling.

What should I do if my dog ate a fly agaric?

Call your vet or an emergency vet straight away. The FDA's 2024 review cites dog poisonings with seizures, and some fatal cases.

Disclaimer: This article is for education only. It is not medical or legal advice. Amanita muscaria is toxic, and it is not sold for ingestion. In an emergency, call your local emergency number.