Oranges: Safe for Dogs and Cats?

Plain orange flesh is safe for dogs in small amounts; the peel, pith, and seeds contain oils and acids that can cause stomach upset and should be removed.

Safe serving: a segment or two of peeled, seedless flesh as an occasional treat

Orange flesh itself is not toxic to cats, but the peel and pith contain essential oils and psoralen that can cause vomiting, diarrhea, or skin irritation, so most vets advise against feeding citrus to cats at all.

Toxic principle: Essential oils and psoralen (peel/skin, not flesh)