Lemons?

Why it’s unsafe

Most dogs dislike lemons, and for good reason. ASPCA lists lemon as toxic to dogs, cats and horses, naming essential oils and psoralens as the toxic principles. Its listing describes vomiting, diarrhea and depression, and possible skin irritation. ASPCA also notes that the fruit itself is edible, so the peel and other plant parts are the larger concern.

The flesh and juice are not poisonous, but they are still a poor choice. PetMD notes that lemon is very acidic, which can irritate the digestive tract and cause vomiting or diarrhea, and that juice is more concentrated than the fruit. Peels and seeds can also cause a blockage.

Small amounts, such as licking a drop of juice, are unlikely to cause serious trouble, but the safest approach is to keep lemons, lemon peel and lemon essential oils away from your dog entirely.

What to give instead

Lemons are not recommended, so there is no serving guide. If your dog is curious about a citrus treat, PetMD says a small piece of orange is acceptable occasionally (see oranges), or choose a safer fruit such as watermelon or blueberries.

Keep fruit bowls, lemon peels, used lemon rinds from drinks and lemon-scented oils out of reach. Lemon trees in the yard should be fenced off or the fruit picked up so your dog cannot chew on windfalls. If you want to flavor your dog's water, plain water or a small amount of safe fruit such as cucumber is a better idea than citrus.

If your dog already ate it

If your dog licked or ate a small piece of lemon flesh, offer water and watch for vomiting or diarrhea, which usually pass.

Call your vet if your dog ate peel, seeds, a whole lemon, or any amount of lemon essential oil, or if vomiting, diarrhea, tremors, weakness, skin redness or lethargy develop. You can also call ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661 (US; fees may apply), or contact your local emergency vet outside the US. Do not try to make your dog vomit at home.