Can dogs eat mushrooms?

With mushrooms, what matters most is where they came from. Ordinary supermarket mushrooms are harmless in small amounts, but mushrooms found outdoors can include deadly species like death cap. Here's the difference, and what to do if you suspect poisoning.

Why not

Toxic compound: amatoxins (in poisonous wild species).

Common cultivated mushrooms like button mushrooms, oyster mushrooms, or shiitake are non-toxic to dogs in small, cooked, unseasoned amounts. They offer no special nutritional value for a dog, though, and raw mushrooms are harder to digest and can upset the stomach.

The real danger comes from mushrooms growing outdoors, in the yard, a field, or the woods. Dogs often pick them up while sniffing around or playing, and it isn't easy to tell an edible species from a poisonous one. Death cap and related species contain amatoxins, which damage the liver and can be fatal even in small amounts.

Poisoning from toxic mushrooms is deceptive because the first symptoms, vomiting and diarrhea, often don't appear until 6 to 12 hours after ingestion and can temporarily fade while liver damage keeps progressing. It can take several days before liver failure becomes apparent, which makes it easy to underestimate the danger.

Because of the risk of misidentification, the safest approach is to never let your dog lick or eat any mushroom growing outside on a walk, even ones that look harmless. If you grow button mushrooms at home, a small cooked piece without onion, garlic, or salt is fine, though it offers no particular benefit to your dog.

Risks

• Poisonous wild and garden mushrooms can cause liver, kidney, or nervous system failure.
• Death cap and related species are potentially fatal even in small amounts.
• It's difficult to tell edible and poisonous species apart, especially when immature or partly decayed.
• Raw store-bought mushrooms can irritate the stomach and cause vomiting or diarrhea.

Symptoms to watch for

• Vomiting and diarrhea, often delayed by 6-12 hours
• Excessive drooling
• Loss of coordination, tremors, seizures
• Jaundice, yellowish gums (liver damage)
• Lethargy, collapse in advanced cases

Your dog already ate mushrooms. What now?

1. If your dog eats a mushroom outdoors and you don't know the species, treat it as a possible poisoning; this is an emergency.
2. If possible, bring a sample of the mushroom, a photo or a piece, to the vet; it helps with identifying the species and choosing treatment.
3. Don't wait for symptoms; with dangerous species they can appear hours later, by which point liver damage may already be advanced. Call your vet or an emergency vet immediately.
4. If your dog ate extra store-bought button mushrooms, monitoring digestion at home is usually enough, and no treatment is necessary.