Can Cats Drink Milk?
Short answer: it is better not to. Most cats lose the enzyme that digests lactose after weaning, so cow's milk often causes diarrhea, gas or vomiting. Kittens need their mother's milk or a kitten milk replacer, never cow's milk. Water is the only drink an adult cat needs.
Why milk upsets cats
Kittens make lactase, the enzyme that breaks down milk sugar (lactose), while they nurse. After weaning most cats make much less of it. Undigested lactose draws water into the gut and ferments, which causes:
- diarrhea, usually within 8 to 12 hours
- gas, bloating and belly discomfort
- sometimes vomiting
Some cats tolerate a little milk without problems, but there is no way to know in advance, and milk adds calories with no benefit.
Kittens: no cow's milk
Orphaned or rejected kittens need a commercial kitten milk replacer (powder or liquid made for kittens), fed with a kitten bottle at the volume and schedule on the label or advised by your vet. Cow's milk does not have the right protein, fat and energy for kittens and can cause life-threatening diarrhea.
Lactose-free "cat milk"
Pet stores sell lactose-free milk made for cats. It is fine as an occasional treat, but it still has calories. Count it in the 10% treat budget:
| Cat's weight | Daily calories (neutered adult) | Treat budget (10%) |
|---|---|---|
| 8 lb | 221 kcal | 22 kcal |
| 10 lb | 261 kcal | 26 kcal |
| 12 lb | 299 kcal | 30 kcal |
For comparison, a tablespoon of whole cow's milk is about 9 kcal, and a tablespoon of cream about 50 kcal. Your own cat's numbers are in the calculator below.
What about cream, cheese and yogurt?
- Cream: less lactose than milk but very high in fat: skip it.
- Cheese: hard cheeses have little lactose; a tiny piece is fine for most cats, but it is salty and fatty.
- Plain yogurt: lower in lactose; a teaspoon is usually tolerated. Never yogurt with xylitol, chocolate or fruit.
Helping a cat drink more water
Many cats drink little, which matters for kidneys and the bladder. Wet food, a water fountain, wide shallow bowls placed away from the food, and several water stations all help.
Sources: PetMD and Cornell Feline Health Center guidance on lactose intolerance; USDA FoodData Central (calories); RER formula as used in WSAVA feeding guidance.
Try the cat food calculator
Enter your own numbers below, or open the full cat food calculator with the formula and more examples.
This guide is general information, not veterinary advice. Your pet may differ: ask your vet. Terms
Frequently asked questions
Is milk bad for cats?
For most adult cats, yes: they are lactose intolerant and get diarrhea or gas. A small amount may be tolerated by some cats, but it has no benefit.
Can kittens drink cow's milk?
No. Kittens need their mother's milk or a kitten milk replacer. Cow's milk can cause severe diarrhea in kittens.
Why do cats like milk so much?
Cats are attracted to the fat and protein in milk, but liking it does not mean they can digest it.
Can cats drink lactose-free milk?
Lactose-free milk made for cats is fine as an occasional treat. Count its calories as part of the 10% treat budget.