Under normal circumstances, many people think that pure milk is the best time to drink at eight or nine o'clock in the morning, because at this time, the human body needs a lot of nutrition. However, in fact, pure milk is the best to drink at night, because milk contains some biochemical ammonia that can make people sleepy and want to sleep. It is very rich in trace morphine, which has a good sedative and hypnotic effect and is conducive to promoting sleep. Moreover, some tryptophan in milk is the main raw material for the brain to synthesize hydroxyl color. Therefore, drinking milk at night is not only conducive to improving the quality of sleep, but also has a good calcium supplement effect. Therefore, it is better to drink milk at night. Calcium can supplement human nutrition, promote human growth, and improve one's immunity. Drinking milk at night can make the human body absorb nutrients better.