The general population is able to drink milk, and inability to drink milk may be due to milk allergy or lactose intolerance. Milk is a common dairy product in daily life and is a good source of high quality protein, vitamins and calcium, which can promote the growth and development of children and adolescents, as well as benefit the bone health of adults. Every 100 grams of milk contains a variety of nutrients such as 226 kcal of energy, 3 grams of protein, 104 milligrams of calcium, 41.1 micrograms of vitamin A, and 109 milligrams of potassium. If you are allergic to milk, you should not drink milk to avoid allergic reactions such as rashes, hives, and breathing difficulties. Milk contains high levels of lactose, if the body lacks lactase, may be lactose intolerant, also can not drink milk, to avoid drinking milk may cause diarrhea, bloating, vomiting and other symptoms. Although milk is rich in nutrients, attention should be paid to the amount of intake, so as not to drink too much to cause discomfort.