The cause of rheumatic heart disease (rheumatic heart disease) is still unclear, and it is currently believed that rheumatic heart disease is related to group A hemolytic streptococcal infection, autoimmune response mechanism, genetic susceptibility, and streptococcal toxin theory. 1. Group A hemolytic streptococcal infection: some patients with rheumatic heart disease have a history of upper respiratory tract streptococcal infection such as pharyngitis and tonsillitis before the onset of the disease. ; 2. autoimmune response mechanism: group A hemolytic streptococcus but some components will produce immune cross-reaction with certain tissues of the body, such as heart valves, attacking the heart valves and causing lesions. 3. Genetic susceptibility: the risk of disease in relatives of patients with rheumatic heart disease is higher than in families without a family history of rheumatic heart disease. 4. Streptococcal toxin theory: Streptococcus bacteria can produce a variety of extracellular toxins and some enzymes, which can directly cause damage to the body’s tissues and organs. Patients with rheumatic heart disease should go to the hospital in time to identify the specific causes, follow the doctor’s instructions for treatment, and consult the doctor if they are not feeling well.