Adults are recommended to drink about 500ml of milk a day, not more than 1000ml. Milk contains a large amount of protein, vitamins, amino acids and trace elements and other nutrients. Drinking less is difficult to play the nutritional value of which, drinking more is not suitable for digestion, absorption and utilization, so the specific amount of milk to drink should be decided according to their age, daily activities and economic conditions. In general, adults should drink 400-500ml a day, that is, two bags, at least 250ml or so, otherwise its nutrients can not play value. Good economic conditions can drink three bags a day, that is, about 750ml, but need to avoid more than 1000ml. In addition, a bag of milk is recommended to drink one hour before bedtime, while two bags of milk need to be distributed morning and evening, three bags of milk should be drunk at three meals, which is conducive to the absorption and utilization of milk nutrients, but it is usually not recommended to drink milk on an empty stomach.