Can Cats Drink Milk?

Usually not. Milk isn’t poisonous to cats, but Cornell’s Feline Health Center says it “is not generally recommended as a treat for cats, as many cats are lactose-intolerant.” Fresh water is the everyday drink, and a kitten that needs milk should get kitten formula, not cow’s milk.

Why milk upsets so many cats

The problem is milk sugar. The ASPCA explains that pets “do not possess significant amounts of lactase,” the enzyme that breaks it down, and Cornell says cats “can develop gastrointestinal problems if fed dairy products.” VCA describes milk upsetting the stomach, causing vomiting and diarrhea.

So a saucer of milk isn’t a poisoning, but for many cats it’s an upset stomach served as a treat. Switching animals doesn’t help: International Cat Care names cow’s, sheep’s and goat’s milk together, and Cornell’s warning covers dairy products in general, so cream and cheese don’t get a pass either.

The sources don’t all say it the same way

The three cat-specific sources agree on the direction but not the strength:

• Cornell Feline Health Center: milk isn’t generally recommended as a treat, because “many cats are lactose-intolerant.”
• VCA: “Cats of all ages should not be fed milk or tuna.”
• International Cat Care: “cow’s/sheep’s/goat’s milk cannot be fully digested by cats so it may cause diarrhoea.”

The ASPCA’s lactase note speaks of pets in general; the three above speak about cats directly. Taken together: not toxic, not needed, and best skipped. If your cat lapped up a little and seems fine, there’s no emergency; just don’t make it a habit.

Kittens: formula, not cow’s milk

Kittens are where the milk myth matters most. VCA says that from about 12 weeks, kittens “lose the ability to digest milk sugar, meaning milk can upset their stomachs, causing vomiting and diarrhea,” and that kittens should get “kitten-specific milk formulas instead.” The 12-week figure comes from VCA alone.

If a kitten has just come home, the new kitten checklist covers the first weeks, and the free New Cat Checklist is there for the setup.

What to offer instead

Offer fresh water as the everyday drink. For treats, Cornell advises “not to let treats exceed 10 to 15 percent of a cat’s daily caloric intake,” and that budget is better spent on treats that don’t upset the stomach. Attention doesn’t have to come from food at all: a few minutes of play does the job too (indoor cat enrichment ideas).

When to call the vet

No source prints a milk amount that calls for a vet visit. Call your vet if vomiting or diarrhea doesn’t settle, or if your cat seems unwell after drinking milk. Note what your cat drank and when, so your vet has the details.

The same VCA page that warns about milk also warns about tuna. For the foods that are truly dangerous, start with onions and garlic. And if your cat shares a home with a dog, see dog food and the guide to dogs drinking milk.