Drinking pure milk for a long period of time is generally not harmful, but milk protein allergy or lactose intolerance can cause digestive discomfort when consuming milk. Pure milk is rich in protein, fat, molybdenum, calcium, iron, phosphorus and so on. Among them, milk protein allergy is predominant in children, mainly manifested as diarrhea and other digestive symptoms. Lactose intolerant people will experience abdominal pain, bloating, diarrhea and other symptoms, it is recommended not to drink milk containing lactose, you can choose lactose-free milk. Pure milk is high in fat, contains unsaturated fatty acids, and also contains some cholesterol, it is not recommended to drink a lot. Pure milk contains more protein, and should not be taken with vitamin C. It is also not recommended to drink it with strong tea or with medicines at the same time. If symptoms of discomfort occur during the consumption of pure milk, you should seek medical attention.