There are many reasons for coughing, which may be related to allergies, infections, side effects of drugs, psychological factors and other conditions. 1. Allergy: Coughing is one of the body’s self-protection mechanisms. For example, inhalation of allergens and stimulation of foreign substances can trigger the body’s reaction and cause the patient to cough. The purpose of coughing is mainly to expel foreign bodies from the respiratory tract or secretions produced by the respiratory tract. 2. Infection: pathological factors may also cause cough, such as acute bronchitis, upper respiratory tract infection, chronic bronchitis, chronic obstructive pulmonary disease, asthma, etc., the respiratory tract secretion increases, the local stimulation can cause cough. 3. Side effects of drugs: some patients cough may be caused by the side effects of drugs, such as taking captopril and other antihypertensive drugs, may cause cough. 4. Psychological factors: mental tension, anxiety and depression and other psychological factors may also cause cough. Occasionally cough, no other discomfort performance, generally do not need special treatment. If the cough symptoms are serious, it is recommended to go to the hospital in a timely manner to identify the cause, under the guidance of the doctor for treatment.