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My 15 kg dog just ate a whole handful of fresh mint leaves. When should I expect to see vomiting or other signs?

Dogs · Food safety

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Short answer

If signs appear, they'll likely start within 2 to 4 hours. A large mouthful of leaves can irritate the stomach lining, leading to drooling, mild stomach gurgling, or a single episode of vomiting. Watch for him turning away from his next meal or seeming uncomfortable when his belly is touched. Offer a small amount of plain water and call your own vet if he vomits more than once or acts lethargic.

Mint leaves — Food safety facts

Feed with care · Dogs · full breakdown on the linked food page

A few fresh leaves are harmless. Concentrated mint oils or a lot of leaves can irritate the stomach.

Dogs and cats carry the same rating (Feed with care), so the notes below hold for either pet.

Mint leaves is not poisonous to dogs, but it is easy to over-feed. Rich fat, salt or seasoning can bring on vomiting or diarrhoea within a day, and repeated large portions are a recognised trigger for pancreatitis.

If it ate some before you noticed, watch for vomiting, diarrhoea, loss of appetite, unusual tiredness or a painful, swollen abdomen over the next 24 hours. A one-off small amount in a healthy adult usually passes with water and rest; repeated exposure, a puppy or kitten, a senior, or a pet with an ongoing illness is a reason to call your vet the same day.

Mint leaves can turn up now and then, but not as a daily habit: keep the rest of the day's food unchanged and watch the next walk and the stool that comes with it.

The full verdict, portion guidance and serving notes are collected on the Mint leaves food facts page.

Open the full food page: Mint leaves food facts →