Is it okay to give my cat milk?
Generally speaking, no, cats shouldn't drink milk. Most cats are lactose (which refers to the sugars in milk) intolerant, and drinking milk may result in an upset tummy or cause diarrhoea. Nutritionally, it is not necessary to give your cat milk. A bowl of water is adequate. Not all cats are lactose intolerant, so a little milk as a treat is fine; however, the only real way to find out if your cat is lactose intolerant is to try feeding it a bowl of milk to see if it causes diarrhoea. If you find your cat is okay with cow's milk, then the occasional bowl is fine; but this should be given as a treat only.
Young kittens MUST have milk in order to survive. The weaning process begins around four weeks of age, but prior to that their only source of nutrition is milk. However, it is of great importance that you do not give a young kitten cow's milk. The best possible milk is from the kitten's own mother. If the kitten is orphaned and a foster cat can't be found for the kitten, then the kitten will have to be given a specially designed "kitten formula", which can be purchased from your veterinarian. This formula is specifically designed for kittens (cow's milk is suitable for baby cows, who have different nutritional requirements than baby cats do).
Cat Milk Alternatives:
If you want to give your cat milk, the safest bet is to purchase special lactose free "cat milk" from your supermarket or pet store. This is far better than giving ordinary cow's milk.
Fresh water should always be available to your cat.