Cats don't drink milk as they are lactose intolerant.

Cats drink milk, but as they grow older, many of them become lactose intolerant. But, not all cats end up suffering from this condition.

Cats drink milk, but as they grow older, many of them become lactose intolerant. But, not all cats end up suffering from this condition. Adult cats are prone to stomach upsets after drinking milk. Lactase is the enzyme that digests lactose present in the cow's milk absent in grown-up cats. Kittens have plenty of these enzymes, and it becomes an ideal food for them. When kittens grow, these enzymes decrease, and it becomes difficult for them to digest milk. According to the Cornell University College of Veterinary Medicine's website, when a lactose-intolerant cat drinks milk, the undigested milk passes through the intestinal tract and drains water along with it.

The small intestine's reduced lactase activity leads to lactose intolerance in some adult cats. The common effects are diarrhea, bloating, and abdominal discomfort. However, there are no documents to show that there is a total absence of lactase in cats. Thus, we can say that all cats are not lactose intolerant and that some adult cats consume milk.