Can Cats Drink Milk?
Last reviewed October 2026 · Based on 2 published veterinary sources (listed below)
Not recommended
Most adult cats lose much of the enzyme (lactase) needed to digest milk sugar after weaning. Cow's milk often causes diarrhea, gas or vomiting. It isn't poisonous, but it isn't needed: water is all an adult cat needs to drink.
Signs milk disagreed with your cat
- Loose stool or diarrhea within 8–12 hours
- Vomiting
- Gassy, uncomfortable belly
Better options
- Fresh water, ideally from a fountain if your cat drinks little
- Lactose-free 'cat milk' as an occasional treat
- Kittens without a mother need kitten milk replacer, never cow's milk
This guide is general information, not a diagnosis. If you're worried about your pet, call your vet or an emergency clinic.