Poisonous mushrooms: recognising the dangers before foraging

Written and medically reviewed by Arnaud, Doctor of Pharmacy and owner of Pharmacie Soin et Nature.

A poisonous mushroom contains substances that can poison humans, from mild digestive upset to serious liver or kidney damage. In France, the national food safety agency (Anses) recorded 1,363 people poisoned between July and December 2024, including 41 serious cases and 3 deaths. In this guide, Arnaud, our pharmacist, explains which species are the most dangerous, why mix-ups are so frequent, which symptoms should alert you and which reflexes to adopt, so that foraging remains a risk-free pleasure.

What exactly is a poisonous mushroom?

Of the thousands of mushroom species found in Europe, only a minority are dangerous. The problem is that these poisonous species often look like sought-after edible mushrooms. Toxicity is described as intrinsic when it belongs to the species itself: this is the case of the death cap, whose toxins resist cooking, freezing and drying.

There is also acquired toxicity. A normally edible mushroom can become dangerous if it is too old, poorly stored, eaten raw, undercooked or picked in a polluted area. Mushrooms accumulate certain heavy metals present in the soil. That is why Anses advises against foraging along roadsides or near industrial sites.

Remember that no simple rule can tell a poisonous mushroom from an edible one. Only precise identification of the species, by a competent person, guarantees a safe meal. By contrast, other mushrooms, such as reishi or shiitake, are used in mycotherapy as food supplements: discover our selection of mycotherapy mushrooms.

How many poisonings by poisonous mushrooms each year?

The toxicovigilance report published by Anses on the 2024 season provides precise figures. Of the 1,363 people poisoned, 41 had a serious form, around 3% of cases. Children under 10 accounted for 55 cases. Among the serious forms, more than half were due to phalloides syndrome, caused mainly by the death cap.

Another figure from the report sheds light on the origin of the problem: of the meals documented, only 27.3% had been checked by someone before being eaten. In other words, the vast majority of people poisoned ate their harvest without having the species verified.

The peak in poisonings follows the peak in mushroom growth, generally from September to November. A wet summer or a mild autumn can shift or extend this period. Every year, health authorities therefore relaunch their prevention messages with the first late-summer rains.

Which poisonous mushrooms are the most dangerous in Europe?

Specialists classify poisonings into syndromes, that is, groups of symptoms linked to a family of toxins. The most useful criterion for assessing severity is the time it takes for symptoms to appear after the meal. The table below shows the main species involved.

Syndromes with a short latency, appearing in less than 6 hours, are the most frequent. They are usually mild with appropriate care, even though they can be impressive. Syndromes with a long latency, appearing 6 hours or more after the meal, are the ones that threaten life: by then, the toxins have already reached the liver or kidneys.

To learn more about the two best-known amanitas, see our article death cap and fly agaric: how to recognise and avoid them.

Why are poisonous mushrooms mistaken for edible ones?

Foragers rarely look for mushrooms at random: they set out to find their favourite species. That is precisely where the trap closes. A young, damaged or poorly lit specimen can show the same colours as the species being sought. The Anses report on the 2024 season lists the most frequent mix-ups.

Popular myths increase the risk. A silver coin that turns black during cooking, a mushroom nibbled by slugs, a pleasant smell or a discreet colour never prove that a species is edible. These “tests” have circulated for centuries even though they have no value. Slugs, for example, eat the death cap without harm.

We describe each dangerous lookalike, with the criteria that help tell them apart, in our article edible mushrooms and their poisonous lookalikes.

How to recognise a poisonous mushroom in the field?

Mycologists examine several elements before giving their verdict:

• The base of the stem: a volva, a kind of membranous sac enveloping the bottom of the stem, points to an amanita. That is why mushrooms should always be picked whole, without cutting them.
• The ring: this collar on the stem exists in many edible and poisonous species. Note whether it is fixed, movable, striated or not.
• The gills or tubes: their colour is decisive. Gills that stay white on a mushroom resembling a field mushroom should alert you, because the field mushroom has pink then chocolate-brown gills.
• The flesh: its change of colour when cut, its smell or texture complete the identification.
• The habitat: the nearby tree, the type of soil or growth in clusters on a stump are valuable clues.

Photo recognition apps have multiplied. Anses strongly advises against them for deciding whether to eat a mushroom, because they carry a high risk of error. A photo shows neither the smell nor the base of the stem, nor the change of colour of the flesh.

What are the symptoms after eating a poisonous mushroom?

Health authorities recall every autumn the signs that should alert you within 12 hours of a meal of mushrooms:

• diarrhoea, vomiting, nausea;
• trembling, dizziness;
• visual disturbances.

The delay between the meal and the first symptoms is the most important information for doctors. According to the Lille poison control centre (France), any poisoning whose symptoms appear 6 hours or more after the meal must be considered serious: it requires hospital care for the person who is ill, but also for all the diners who shared the dish.

The trap of phalloides syndrome lies in how it develops. After a very violent digestive phase, symptoms can ease for one or two days. This misleading improvement comes before the liver damage. Hence the importance of seeking help even if you feel better.

At the pharmacy, we notice that people who come in after a meal of mushrooms often think it is simple indigestion, especially when the problems start the next morning. This late onset is precisely the signal that should worry you.

All the syndromes, their timing and how they develop are detailed in our article mushroom poisoning: symptoms, timing and what to do.

What to do after eating a poisonous mushroom?

When poisoning is suspected, every hour counts. Here are the reflexes recommended by health authorities:

• Call straight away: 112 anywhere in Europe. In the UK, call 999 or NHS 111. In Ireland, the Public Poisons Line is available on 01 809 2166 (8am to 10pm). Say that you have eaten mushrooms, even if the symptoms seem mild.
• Note the times: the time of the last meal containing mushrooms and the time the first symptoms appeared.
• Keep the leftovers of the harvest, raw or cooked, as well as the peelings. They will help identify the species involved.
• Show the photo of your harvest if you took one before cooking.
• Warn everyone who shared the meal, even if they feel nothing for the moment.

Do not take any medicine for diarrhoea or vomiting on your own initiative. These symptoms are part of what the doctor needs to assess. Self-medication can also mask how the poisoning develops. Treatment is exclusively a matter for the medical teams.

Where to have a poisonous or doubtful mushroom checked?

In France, pharmacists have long been foragers’ natural point of contact. However, practical mycology now plays a reduced role in pharmacy studies, and the situation varies from one pharmacy to another. In other countries, mushroom identification is usually handled by mycological societies or, in some regions, by public mushroom inspection services.

Mycological societies often hold identification sessions during the season, as well as guided outings and exhibitions. It is an excellent way to learn to recognise the species of your region with experienced enthusiasts.

In all cases, present whole mushrooms, sorted by species, in a basket or a cardboard box. A cut mushroom or one mixed with others cannot be identified with certainty. If the slightest doubt remains, the rule is simple: do not eat it.

How to forage without the risk of poisonous mushrooms?

Anses recommendations cover every step, from forest to plate:

• Before you go: take a basket or a cardboard box, never a plastic bag, which speeds up rotting.
• While foraging: avoid roadsides, industrial areas and landfill sites. Only pick specimens in good condition, neither too young nor too old.
• When sorting: separate the species to prevent a poisonous fragment from contaminating the others. Photograph the harvest before cooking.
• When storing: keep mushrooms in the fridge for two days at most.
• When cooking: cook wild mushrooms thoroughly, in reasonable quantities. Never serve them to young children.

Vigilance also applies close to home. Dangerous species grow in lawns, meadows or at the foot of hedges, where children and pets play. We look at this in our article poisonous garden mushrooms: which ones to watch for.

What else should you know about poisonous mushrooms?

Does cooking destroy the toxins of a poisonous mushroom?

No, not in the most serious cases. The toxins of the death cap resist cooking, freezing and drying. Cooking remains essential for wild edible mushrooms, but it never makes a poisonous mushroom edible.

Is a mushroom eaten by slugs edible?

No. Slugs and other animals eat mushrooms that are deadly to humans, including the death cap, without harm. This criterion, like the silver coin that turns black, is one of the myths to forget.

Can you rely on an app to identify a mushroom?

No. Anses strongly advises against recognition apps for deciding whether to eat a mushroom, because of a high risk of error. They can be a starting point for learning, never a validation before a meal.

Are children more exposed to poisonous mushrooms?

Yes. Their low body weight makes them more sensitive to toxins, even in small amounts. Anses recommends never giving wild mushrooms to young children. Also keep an eye on mushrooms growing in the garden, which a toddler could put in their mouth.

When should you seek help after eating a poisonous mushroom?

Seek help as soon as digestive problems, trembling, dizziness or visual disturbances appear after a meal of mushrooms, by calling 112 or a poison centre. Symptoms that appear 6 hours or more after the meal signal potentially serious poisoning, even if you then feel better.

Sources

• Anses (France), Accidental mushroom poisoning, toxicovigilance report (2024 season)
• Lille poison control centre, Lille University Hospital, Mushrooms and main toxic syndromes
• National Poisons Information Centre of Ireland, Mushroom safety advice
• NPIS (UK), Information for members of the public
• Santé publique France, National surveillance of mushroom poisoning, Weekly Epidemiological Bulletin