Although many television shows, comic strips, and other stories about cats tend to portray cats as lovers of all things milk, the product itself is actually not recommended for cats. Your vet can tell you that not all cats including your Siberian should drink milk as it may be hard for them to digest. Although young cats or kittens are able to digest milk, it is believed that as they age they lose the enzyme that enables digestion. The main reason for indigestible milk is the lactose inside. Your Siberian may not be able to digest lactose. If this is the case, it will ferment in the stomach causing diarrhea or in worse cases vomiting. Symptoms of lactose intolerance usually occur within 8 to 12 hours. If your Siberian cat has diarrhea or is vomiting, please call your veterinary clinic Leesburg, VA right away. Some cats may be able to tolerate other dairy products such as yogurt and cheese.