Milk can supplement the body with high-quality protein, fat, carbohydrates, vitamins, inorganic salts, calcium, phosphorus, potassium, magnesium and other nutrients. The nutrition of milk is easily absorbed, and drinking milk in moderation can improve the body’s immunity and prevent chronic diseases, and can be consumed in small amounts one hour before bedtime. But if it means drinking milk at night before going to bed, it may have the harm of affecting sleep, dental caries, causing fat accumulation, increasing gastrointestinal burden, etc. 1. affecting sleep: drinking milk before going to bed may increase the water in the body, leading to an increase in the number of urination at night, thus affecting the quality of sleep; 2. dental caries: especially for children, drinking milk before going to bed, if the teeth are not thoroughly cleaned, milk in the mouth If children drink milk before going to bed, if they do not clean their teeth thoroughly, the fermentation of milk in the mouth will cover the mucous membrane and teeth surface, which will easily cause tooth decay; 3, lead to fat accumulation: human metabolism will be slowed down during sleep, and milk contains protein and fat, if they drink whole milk before going to bed, it will easily lead to fat accumulation and obesity; 4, increase the gastrointestinal burden: at night, activity is reduced, metabolism is slowed down, gastrointestinal peristalsis is slowed down, drinking milk before going to bed may lead to increased gastrointestinal burden, resulting in bloating and other uncomfortable symptoms. The appearance of abdominal distension and other uncomfortable symptoms. In addition, lactose intolerance, milk allergy, post-abdominal surgery patients, iron deficiency anemia, cholecystitis, pancreatitis and other patients, should not drink milk.