The causes of afternoon dry mouth phenomenon include: physiological factors, drug factors, oral diseases, dry syndrome, diabetes and so on. 1. Physiological factors: such as excessive salt intake of food at noon, high indoor temperature, too much exercise, etc., will cause the phenomenon of thirst, leading to dry mouth in the afternoon performance, you can drink warm water to alleviate the symptoms. 2. Drugs: some drugs can also lead to the emergence of dry mouth adverse reactions, such as reserpine, methyldopa, etc., if the adverse reaction is serious, you can follow the doctor’s instructions to reduce or change the drug. 3. Oral diseases: for example, mumps, oral gland stones and other diseases, will cause the salivary glands in the oral cavity to secrete saliva to reduce the amount of saliva, which in turn leads to the performance of dry mouth and tongue. 4. Dry Syndrome: An autoimmune disease that is caused by the production of a special antibody in the patient’s own body that destroys the salivary glands. Although the antibody also destroys other parts of the body, it is particularly severe in the oral cavity, leading to a decrease in saliva production, which in turn leads to symptoms of dry mouth. 5. Diabetes: Especially in the early stages of the disease, it is often characterized by dry mouth, thirst and other unpleasant symptoms. The diagnosis can be confirmed through fasting blood glucose and two-hour postprandial blood glucose measurements. These are only some of the common causes. As you can see, the occurrence of dry mouth in the afternoon has both physiological and pathological causes. It is recommended to consult a doctor in time and follow the doctor’s instructions for standardized treatment after a clear diagnosis. The use of drugs must follow the doctor’s instructions, not blindly use their own drugs, so as not to cause adverse consequences.