Milk is an alkaline food. The acidity or alkalinity of food is determined according to the chemical properties of the ash obtained from the combustion of food, which is alkaline if it contains more potassium, sodium, calcium and magnesium, and acidic if it contains more phosphorus, bowl and hydrogen. Milk is alkaline according to its acidity or alkalinity, because milk produces more sodium, potassium, magnesium and calcium when it enters the human body through metabolism, which tends to produce more alkali in the human body. The acidity and alkalinity of food does not affect the acidity and alkalinity of the human body, the human body has the function of regulating the body’s acidity and alkalinity will be maintained in a relatively balanced state. Milk is a high quality food source of protein and calcium. The Dietary Guidelines for Chinese Residents recommends 300ml of milk per day to ensure a balanced diet. Lactose intolerant people should not drink milk, so as not to induce diarrhea, skin rashes and other allergic reactions, affecting health.