Grape juice is best not to mix with milk to drink, the original I also tried two things mixed up, found that will produce reactants, and then I asked when the doctor's sister, only to know that the milk meets the grape juice in the acid will produce indigestible precipitates, often drink easy to cause gastric and stone disease, while the original two highly nutritious food will lose a variety of nutrients, for example, milk in calcium The loss of calcium in milk, for example, (and acidic substances in grape juice chemical reaction), milk is a weak alkaline food, while the grape juice is acidic, heh heh heh! Imagine the consequences! By the same token, milk and fruits like orange juice should not be mixed! Don't compromise your health because of taste!