It depends on the individual drinker and the type of milk.

For example:

People who are intolerant to cow's milk may suffer from diarrhea and indigestion.

People with renal insufficiency may drink too much milk, which may lead to high blood ammonia.

People with high blood fat may be aggravated by drinking whole milk, or high-fat milk.

But for the average healthy adult, one pound (500 milliliters) a day is generally good for the body