Patients with hemoptysis should have careful and repeated chest examinations. Some chronic heart and lung diseases can be combined with disobedient fingers (toes), and patients with progressive tuberculosis and lung cancer often have significant weight loss. Some hematologic diseases suffer from a general bleeding tendency. Hemoptysis with skin and mucous membrane bleeding must be identified according to the following primary diseases: 1, leptospirosis: leptospirosis is a systemic infection disease, the course of the disease is often self-limiting, due to individual differences in immune levels and strains of bacteria, clinical manifestations can vary in severity. Mild self-limiting fever can be mild; severe cases can show symptoms of acute inflammatory liver injury, kidney injury such as jaundice, hemorrhage, uremia, etc., and inflammatory symptoms of meninges such as mental disorders and meningeal irritation signs; severe patients can develop liver and kidney failure, pulmonary hemorrhage or even death. 2, epidemic hemorrhagic fever: hemorrhagic fever is a natural epidemic disease caused by epidemic hemorrhagic fever virus, mainly transmitted by mucous membranes and broken skin, with fever, hemorrhagic tendency and kidney damage as the main clinical features of acute viral infectious diseases. At present, the disease is widespread, with a high death rate and greater harm, is one of the national priorities for the prevention and control of infectious diseases. 3, hematological diseases: hematological diseases are diseases that originate in the hematopoietic system or affect the hematopoietic system with abnormal blood changes, characterized by anemia, bleeding and fever. Common clinical disorders include leukemia, aplastic anemia, myelodysplastic syndrome, thrombocytopenia, multiple myeloma, etc. 4, connective tissue disease: connective tissue disease is a group of diseases based on the pathology of mucus-like edema and fibrin-like degeneration of loose connective tissue. The etiology is not very clear, and is generally considered to be related to genetics, immunity and viral infection, and is a multi-causal disease. With the progress of immunology, it is found that most connective tissue diseases are associated with immunological abnormalities, such as suppressive T-cell hypofunction, humoral immune hyperfunction, and the presence of autoantibodies in some connective tissue diseases, so this group of diseases is also classified as immune diseases or autoimmune diseases. Hemoptysis with chest pain is most often seen in pulmonary infarction pneumococcal pneumonia; hemoptysis with choking cough is most often seen in bronchopulmonary carcinoma, mycoplasma pneumonia: hemoptysis with sputum is seen in lung abscess; massive hemoptysis is most often seen in cavitary tuberculosis, ruptured bronchial dilatation aneurysm, etc. Domestic literature reports that leptospirosis without jaundice has also caused pathogenic hemoptysis.