Poisonous mushrooms and your dog: how to spot the symptoms and what to do

August 26 2026, by Michael van Wassem, 7 min reading time

During an autumn walk, a mushroom can suddenly appear on the path — and not every dog can resist the temptation. Here is how to recognise the symptoms of mushroom poisoning and how to respond.

Your dog is sniffing happily through the fallen leaves, and before you know it, he has a piece of mushroom between his jaws. Are mushrooms dangerous for dogs? The short answer: some species are, and the effects can be serious — from vomiting and diarrhoea to liver damage or worse. Because it is nearly impossible for a layperson to tell poisonous and harmless mushrooms apart, the rule is always the same: if in doubt, call the vet. In this article, you will read which symptoms to watch for, what to do immediately, and how to stop your dog from taking a bite during a walk.

Why are mushrooms dangerous for dogs?

Of the thousands of mushroom species found in the UK and the rest of Europe, only a small number are poisonous — but that small number can have very serious consequences. Poisonous mushrooms contain different types of toxins that damage the body in different ways: some mainly irritate the stomach and intestines, others attack the liver, and a few can affect the nervous system. The problem is that poisonous and harmless mushrooms often look very similar, especially to a layperson. Even experienced mushroom experts sometimes struggle to tell them apart with certainty in the field. For your dog, that distinction is even harder to make — he smells and tastes, and that is exactly the risk.

Which mushrooms are the most dangerous?

A few species stand out because of how seriously toxic they are:

• Death cap (Amanita phalloides): one of the most poisonous mushrooms there is. Even a small piece can be life-threatening. You will mostly find it in deciduous woodland, near oak, beech and hazel trees, from summer into autumn.
• Fly agaric (Amanita muscaria): the well-known red mushroom with white spots. Contains substances that can cause vomiting, coordination problems and sometimes seizures.
• Panther cap (Amanita pantherina): resembles other amanitas and works similarly to the fly agaric, but is even more toxic.
• Devil's bolete and other poisonous boletes: mainly cause severe stomach and intestinal problems.

⚠️ Note: you do not need to know the exact species to act. Has your dog eaten a mushroom, or is there a nibbled one lying around? Contact the vet regardless, even if you are unsure whether it is a poisonous species.

Recognising the symptoms of mushroom poisoning

The symptoms depend on the type of toxin and can vary greatly in timing: sometimes within 15 minutes, but with some liver toxins only after 6 to 12 hours — which makes it especially deceptive, since by that point you may no longer be thinking about the mushroom. Watch for the following signs:

• Vomiting and diarrhoea (sometimes with blood);
• Abdominal pain, restlessness or a bloated belly;
• Excessive drooling;
• Lethargy, weakness, or conversely a fast heart rate;
• Uncoordinated movements or trembling;
• Yellowing of the gums or the whites of the eyes (a sign of liver damage);
• Seizures or coma in severe cases.

Is your dog showing a combination of these signs, and might he have eaten something outside? Do not wait to see if it passes on its own.

What should you do if your dog has eaten a mushroom?

1. Call the vet or an emergency clinic immediately — even outside opening hours. With mushroom poisoning, every minute counts.
2. If possible, take a piece of the mushroom with you, or take a clear photo. This helps the vet determine the right treatment faster.
3. Do not make your dog vomit yourself unless the vet explicitly advises it — with some toxins, vomiting can actually make things worse.
4. Note the time you think your dog ate the mushroom and which symptoms you are seeing, so you can pass this on.
5. Follow the vet's instructions closely, even if the first checks do not show serious damage: some toxins only take effect later.

When and where is the risk highest?

Mushrooms mostly appear after a period of rain followed by milder temperatures — usually from July through November, peaking in September and October. Damp deciduous woodland, verges, and even your own garden after a rain shower are favourite growing spots. Dogs that naturally sniff a lot and eat everything — think of Labradors and other food-driven breeds — carry a higher risk, but in principle any dog can be tempted.

How to stop your dog eating mushrooms

Full control over what a dog sniffs out and picks up during a woodland walk is difficult, but this approach cuts the risk considerably:

• Keep your dog on the lead in areas where mushrooms are growing, especially in autumn. A sturdy training leash gives your dog room to sniff while still letting you step in in time.
• Train a solid "leave it" cue. This is one of the most useful commands you can teach a dog; you will find suitable training gear in our training, sport & behaviour category.
• Consider a muzzle for dogs that consistently eat anything they find on the ground. A light, comfortable muzzle stops them picking things up, without making it impossible to drink or pant.
• Check your garden regularly for mushrooms, especially after rain, and remove them wearing gloves before your dog can reach them.
• Be extra alert during woodland and countryside walks in autumn, when mushrooms grow in abundance.

💡 Tip: a well-trained "leave it" does not happen overnight. Practise at home first with neutral objects, and only build up to distracting outdoor situations afterwards.

Common mistakes

• Waiting to see if the symptoms pass on their own. With mushroom poisoning, delay can make the damage irreversible.
• Assuming a small bite cannot cause harm. With some species, such as the death cap, even a small piece can potentially be fatal.
• Inducing vomiting yourself without advice. This is not a good idea with every toxin and can do harm without expert guidance.
• Not bringing a mushroom or photo to the vet. Without identification, treatment is harder to determine.
• Assuming only woodland walks carry a risk. Your own garden and the local park can contain poisonous mushrooms too.

Frequently asked questions

Are all mushrooms poisonous to dogs?

No, most mushrooms you come across on a walk are not poisonous. Still, the difference between poisonous and harmless species often cannot be determined with certainty by a layperson, so caution is always wise.

How quickly should I get to the vet if my dog has eaten a mushroom?

As quickly as possible. Do not wait for symptoms: with some poisonous species, the first signs only appear after hours, by which time the damage has already been done.

Can my dog eat ordinary mushrooms from the supermarket?

Raw or cooked mushrooms in small amounts are usually not a problem for most dogs, but never give them prepared with garlic, onion, or a lot of salt or fat. If in doubt, check with your vet.

Can a cat be poisoned by mushrooms too?

Yes, cats can also become ill from poisonous mushrooms, although it happens less often than with dogs, because cats tend to be fussier eaters and roam freely through woodland less often. The same precautions apply.

Summary and conclusion

Mushrooms are part of autumn, but not every species is harmless to your dog. If you spot symptoms such as vomiting, diarrhoea, lethargy or yellowing gums after a walk, call the vet straight away, take a piece of the mushroom with you, and do not wait. Prevention remains the best approach: keep your dog on the lead in risk areas, train a reliable "leave it", and check your garden regularly.

Looking for the right gear for safe walks this autumn? Browse our dog muzzles, or pick up a sturdy training leash for extra control along the way.

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Gezondheid & Preventie Herfst Honden Kennisbank Seizoensverzorging

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