My dog ate a mushroom: what to do, and which UK mushrooms are dangerous to dogs

If your dog has eaten a wild mushroom, call your vet straight away, even if it seems perfectly well. The most dangerous mushroom in Britain, the death cap, causes no signs at all for the first 6 to 24 hours, and by the time a dog looks ill, precious treatment time has gone.

Most mushrooms dogs pick up in gardens and parks cause no signs or just an upset stomach. A few kill. You can't tell which kind it was by looking at your dog in the first hours, and you usually can't tell by looking at the mushroom either. That's the whole reason this article starts with what to do, and only then explains why.

What to do right now

Ring your vet now, not when symptoms start. Here is the order that saves time:

1. Phone your vet. If the practice is closed, call your nearest out-of-hours vet. You can also call Animal PoisonLine on 01202 509 000. It's run by the Veterinary Poisons Information Service, answers 24 hours a day and tells you whether your dog needs to be seen; a fee is charged per call.
2. If your dog has collapsed, is fitting or is struggling to breathe, don't phone a helpline. Go to a vet straight away, and call them on the way.
3. Don't try to make your dog sick. Salt water can be fatal, and hydrogen peroxide damages the stomach lining. Whether to make your dog vomit is your vet's decision, and they have safe ways of doing it.
4. Take the mushroom with you, but don't let it delay you. If you can do it quickly and safely, pick a whole, undamaged one (or several) from the same spot, wearing gloves. Wrap it in paper or put it in a paper bag, not plastic. Take photos of it and of the place where it grew: lawn, under a tree, on a stump. Keep other pets and children away from the patch, and wash your hands afterwards.
5. If your dog has already been sick, take a photo of the vomit and, wearing gloves, a sample in a bag. Pieces of mushroom in it can help identify what was eaten.
6. Note the time and roughly how much your dog ate.

Bits of chewed mushroom can be impossible to identify, which is why a fresh specimen from the same patch helps so much. Vets can send a description and photos to the Veterinary Poisons Information Service, which works with mycologists.

Why you shouldn't wait for symptoms

Waiting is dangerous because the two worst kinds of poisoning behave in opposite ways.

The death cap works slowly. Vomiting and diarrhoea usually start 6 to 24 hours after eating. Then many dogs seem to get better for 12 to 24 hours. Owners relax, and that's exactly when the liver is failing: the serious damage shows 36 to 72 hours after the mushroom was eaten. Death cap poisoning is often fatal in dogs, although some survive with fast, intensive treatment, and the earlier it starts, the better the chances. In a Californian study of 59 dogs poisoned by mushrooms containing the same toxins, 13 survived to go home.

Other mushrooms work fast. Small white funnel mushrooms and fibrecaps, which grow on lawns and verges, can cause drooling and vomiting within minutes to two hours. So "it's been an hour and he's fine" tells you nothing either way.

Can dogs eat mushrooms?

Plain shop-bought mushrooms, such as button or chestnut mushrooms, are generally considered safe for dogs in small amounts. Wild mushrooms are not, because even experienced foragers can't guarantee an identification from a quick look.

The bigger risk in the kitchen is the dish, not the mushroom. Don't share mushrooms cooked with onion, garlic, butter or seasoning. Onion and its relatives are among the most common things the UK poisons service is asked about, and onion can kill a dog.

Which mushrooms are poisonous to dogs in the UK

Treat every wild mushroom as potentially poisonous until a specialist says otherwise. These are the ones that matter most in Britain:

Death cap

The death cap (Amanita phalloides) causes vomiting and diarrhoea 6 to 24 hours after eating, an apparent recovery, then liver failure at 36 to 72 hours. It has killed dogs in the UK. It grows mainly with oaks, also with other broadleaf trees, from July to November, and is quite common in most of Britain.

Fly agaric and panther cap

Fly agaric (Amanita muscaria) and panther cap (A. pantherina) cause vomiting, then wobbliness, twitching, drowsiness or seizures, usually 20 minutes to 4 hours after eating and sometimes later. Deaths are rare but recorded. Fly agaric grows with birch, pine and spruce; panther cap mostly under oak or beech, from August to November.

Fool's funnel, frosty funnel and fibrecaps

Fool's funnel (Clitocybe rivulosa), frosty funnel (C. phyllophila) and fibrecaps (Inocybe) cause drooling, vomiting, diarrhoea, a slow heartbeat and collapse within minutes to 2 hours. Mushrooms in this group have killed dogs in the UK. Look for them on verges, parkland, paths, woodland and garden lawns from late June to early December.

Earthballs

The common earthball (Scleroderma citrinum) and other earthballs have caused vomiting, drooling, lethargy, and sometimes fever or a racing heart. Every dog in the published UK cases recovered. In people, signs usually start within a few hours. Earthballs are very common on sandy soil, forest tracks and banks from July to early December.

Deadly webcap

The deadly webcap (Cortinarius rubellus) damages the kidneys, and the signs come late: usually after 2 to 3 days, sometimes longer. It grows with pine and spruce on damp acid soil, and is rare in southern England but commoner further north.

Liberty cap

The liberty cap (Psilocybe semilanceata) usually causes wobbliness and odd behaviour within 30 minutes to 4 hours, occasionally agitation, overheating or seizures. It grows in grassland, mostly upland pastures, and sometimes on lawns.

Small brown lawn mushrooms

Small brown lawn mushrooms all look alike, and some of them, such as funeral bell (Galerina) and some small dapperlings (Lepiota), contain the same toxins as the death cap. Never assume a little brown mushroom is harmless.

What real UK cases show

The UK's poisons service publishes real cases every year, and they show both sides. In 2020 a pug that wasn't thought to have eaten much of a frosty funnel mushroom in its garden was vomiting and collapsed within an hour, and died 10 hours later. Dogs were put to sleep after eating death caps in 2023 and 2024. Yet most of the dogs in those same tables were fine throughout or recovered fully, including every dog that ate an earthball.

Two warnings about looks. Dangerous mushrooms aren't all red with white spots: the UK deaths where the mushroom was identified involved a death cap, which is usually greenish but can be pale yellow or almost white, and small white funnel mushrooms. And phone apps are no help here: in an Australian study the best app identified only 49% of mushrooms correctly, and 44% of the poisonous ones. A photo check can't clear your dog.

Symptoms of mushroom poisoning in dogs

The signs depend on the toxin, and a dog can show more than one group:

• Stomach: vomiting, diarrhoea, tummy pain, refusing food. Usually within a few hours, sometimes much later.
• Drooling and a slow heart: heavy drooling, watery eyes, diarrhoea, weeing, a slow heartbeat, collapse. Typical of funnel mushrooms and fibrecaps, within two hours.
• Nervous system: wobbling, twitching, flickering eyes, drowsiness, seizures. Typical of fly agaric and panther cap.
• Liver: after a death cap, weakness, bleeding or collapse as the liver fails, often after a day when the dog seemed better.
• Kidneys: kidney failure that only shows days later. Typical of webcaps.

Don't wait to see which group your dog falls into. Call as soon as you know or suspect it ate a wild mushroom.

What happens at the vet

If your dog gets there early, the vet may make it vomit safely and give activated charcoal to soak up what's left. After that, treatment is support: a drip, anti-sickness medicine, sugar if blood glucose drops, plasma if the blood stops clotting properly, and medicine to counter drooling and a slow heart after funnel mushrooms or fibrecaps.

Expect blood tests. After a possible death cap, vets check the liver, blood sugar and clotting, often more than once, and may ask to recheck a couple of days after your dog goes home.

Puppies are most at risk

Puppies eat anything, and the numbers show it. In a Norwegian study of 421 dogs that ate mushrooms, the median age was 5 months and almost three quarters were under a year old. In the Californian study, most of the 59 dogs were under a year old. Young dogs can also deteriorate faster: a puppy poisoned by these liver toxins can die within a day, and in 2024 a fatal death cap poisoning in a 5-month-old puppy was reported in a toxicology journal.

If you have a puppy, autumn walks need a closer eye, and lawns are worth checking every morning.

Mushrooms in the garden: how to keep your dog safe

Most cases happen from late summer into autumn, especially after rain, so that's when a daily look round the garden pays off. Pick off any mushrooms you find, wearing gloves.

They will come back. The mushroom is only the fruit of a fungus that lives on in the soil or in buried wood, and there are no fungicides for toadstools in UK lawns. Regular picking is the practical answer, and a lead or a firm "leave it" in parks where you've seen mushrooms.

What about cats?

Cats are reported far less often than dogs, but they can still be poisoned, so the advice is the same: call your vet straight away and bring the mushroom.

Myths that put dogs at risk

• "He's been fine for a couple of hours, so it was harmless." The death cap gives no signs for 6 to 24 hours and can then seem to ease off before the liver fails.
• "Only red, spotty toadstools are poisonous." The identified UK dog deaths in recent years came from a greenish-white death cap and small white funnel mushrooms.
• "Little brown lawn mushrooms are harmless." Some contain the same toxins as the death cap.
• "Give salt water to make him sick." It can be fatal. Leave vomiting to the vet.
• "The app said it's edible." Apps get poisonous mushrooms wrong more often than right.
• "Hallucinogenic mushrooms are just a funny trip." Fly agaric has killed dogs, even if it rarely does.

If in doubt, there's no doubt: ring the vet. You'll never regret a call that turned out unnecessary.