Many people drink alcohol at night, the second half of the night will appear dry mouth, serious cases can appear the whole mouth is dry, need to drink water often to solve the problem of dry mouth. Because after alcohol enters the body, it will stimulate the kidneys, increase the filtering effect of the kidneys, which leads to increased urination, causing dry mouth in the second half of the night. When alcohol dissolves in the blood into the body cells, the extracellular osmotic pressure is significantly higher than the intracellular osmotic pressure, which will prompt the intracellular fluid permeation to the outside of the cell, the cell is temporarily dehydrated, and part of the water stored in the body is discharged by the kidneys to the outside of the body. Reduced body water, through the nerve reflex system to stimulate the human body, produce the feeling of thirst, prompted by drinking water to replenish the missing water, so it is advisable to drink a lot of boiled water and light tea after drinking alcohol, in order to replenish the body’s water in a timely manner. The night is the organs rest time, drinking at night will increase the metabolic burden of the organs, especially the kidneys and liver, its work needs to consume water, less drinking water at night, so drinking at night, the second half of the night dry mouth will be more obvious, it is recommended that weekdays as little as possible to drink alcohol. Drinking alcohol can cause a lot of harm, such as alcoholic hepatitis, cirrhosis of the liver, obese people drink a lot of alcohol at night may cause asphyxiation, triggering sudden death and other serious situations.