Most cats are lactose intolerant, but not all. Some individual cats can handle small amounts of dairy without obvious issues, yet milk is still not recommended as a regular treat.

Quick Scoop

  • Most adult cats are lactose intolerant , because they lose much of the enzyme (lactase) needed to digest milk sugar as they grow out of kittenhood.
  • Kittens can digest their mother’s milk, but that does not mean they’ll tolerate cow’s milk or stay tolerant as adults.
  • A minority of cats can drink a little milk without diarrhea or gas, but there is no way to know for sure without trial, and even then the benefit is minimal.

What “Lactose Intolerant” Means for Cats

  • Lactose is the sugar in milk; lactase is the enzyme that breaks it down in the small intestine.
  • As cats mature and switch to solid food, lactase production usually drops, so undigested lactose ferments in the gut and pulls in water.
  • This can cause diarrhea, gas, cramping, and a very messy litter box 8–12 hours after drinking milk.

Are All Cats Lactose Intolerant?

  • No one has tested every cat, and some cats clearly tolerate small amounts of milk without obvious problems.
  • However, experts and veterinary sources agree that most adult cats are lactose intolerant “to some degree,” so it’s safest to act as if yours is.
  • Wild and feral adult cats also have no natural need for milk, so there’s no evolutionary pressure for lifelong lactase production.

If Your Cat Loves Milk

  • Like people, cats often want foods that aren’t good for them; attraction does not equal safety.
  • If you ever offer dairy, keep it to a teaspoon or two, very occasional, and watch closely for loose stool, vomiting, or discomfort.
  • Lactose-free “cat milk” products are safer options but should still be rare treats, not a daily drink.

Safer Treat Ideas

  • Small portions of plain cooked meat (chicken, turkey, or fish with no seasoning or bones).
  • Commercial cat treats formulated for digestive safety and balanced nutrition.
  • For most cats, fresh water plus a complete cat food is all that’s needed for long-term health.

In practice: assume your cat is lactose intolerant unless a vet says otherwise, and treat dairy (if any) as an occasional, tiny indulgence—not a staple.

Information gathered from public forums or data available on the internet and portrayed here.