Experts agree: Most dogs shouldn't drink milk. More often than not, they're lactose intolerant, and they simply can't stomach the enzymes in milk and most dairy products. Even ice cream can be difficult for your dog to digest, so play it safe and only give him products formulated especially for canines. If he gets his hands on some milk, you don't have much to worry about -- while it will make him uncomfortable, the indigestion will pass.
Take away any milk to which your dog has access. If a glass spilled, for example, clean it up before he can drink any more -- while it can upset his stomach, all he understands is that it tastes great.
Give your dog plenty of fresh, cool and clean water to drink. Depending on his level of intolerance and how much milk he drank, he may experience diarrhea or vomiting, which will quickly dehydrate him.
Take him out for frequent bathroom breaks. If he experiences gastrointestinal upset and diarrhea, he's going to be going No. 2 more than usual.
Give him a moisturizing oatmeal bath if he seems itchy. Many dogs are allergic to milk and dairy products, and experience itchy skin as a result. A soothing bath can help him relax.
Offer your dog a substitute in the future, like canned milk or milk formulated for dogs.