Bronchiectasis is one of the common chronic diseases in internal medicine, and patients may present and cough up sputum, cough, hemoptysis and other clinical manifestations. For the causes of bronchiectasis there are several: 1. Genetic diseases: cystic fibrosis is the most common genetic disease in bronchiectasis. Cystic fibrosis is usually caused by the relatively weak development of connective tissue in the muscle. 2, the body is infected: infection is the most common cause of bronchiectasis in the body, mainly due to infection of the lungs, for example: whooping cough, tuberculosis, adenovirus pneumonia, etc. 3, the body immune deficiency: If one or more immunoglobulins in the organism show symptoms of deficiency, it is easy to cause patients to develop bronchial dilatation. 4, abnormal cilia: abnormal cilia structure and function is also one of the main causes of bronchial dilatation. 5, foreign body into: If the body because of breathing caused foreign body into the airway, long-term presence will lead to chronic obstruction and inflammation of the body, thus causing bronchiectasis. Usually the body suffers from bronchiectasis caused by the above five reasons, according to the severity of the disease, promptly take treatment.