The best time to drink milk is at night before going to bed. First, because milk has hypnotic effect; Second, the rich calcium in milk can meet the demand of calcium in blood at night and protect bones from damage. The human body's demand for calcium is a continuous process. After falling asleep at night, the stomach and intestines are at rest, and the calcium level in the blood is reduced. Drinking a glass of milk before going to bed is not only beneficial to sleep, but also makes the disease prevention function of milk play a better role.