It is generally better to drink milk half an hour to an hour before going to bed, preferably warm, with the amount controlled at about 200ml. Milk is rich in calcium and protein, and drinking milk half an hour to an hour before bedtime will not allow the peak of calcium metabolism in milk to occur during sleep, avoiding the accumulation of calcium in the urinary system and increased nocturnal urination, and can prevent cramps in the hands and feet caused by calcium deficiency at night, prevent rickets in children, osteoporosis in the elderly, and also improve the immune system. In addition, milk contains traces of morphine-like substances and tryptophan components, which can soothe the nerves, play a calming and sleeping effect, and improve the quality of sleep. Milk should be avoided with chocolate, because the oxalic acid in chocolate will affect the absorption of calcium, and try not to take it with herbs or western medicine to avoid reducing the effectiveness of the medicine.