Bleeding from brushing teeth is actually bleeding gums, which is mainly caused by inflammation of the gums or blood system diseases, and requires periodontal treatment or hematological specialist treatment. 1. Inflammation of gums: poor oral hygiene will produce a lot of tartar or calculus adhering to the surface of the teeth, which will stimulate the gum tissues leading to infection and inflammation of the gums and the symptoms of gum tenderness and swelling; and then the gums are stimulated by the brushes and other hard objects during brushing and the symptoms of bleeding. 2. Blood system diseases: leukemia, hemophilia or idiopathic thrombocytopenic purpura will lead to abnormal blood coagulation, which will lead to the skin or mucous membranes are susceptible to external trauma and not easy to stop the bleeding symptoms; so when brushing the gums by the trauma of brushes and other hard objects will appear bleeding symptoms. Brushing teeth bleeding persists unrelieved recommend timely medical diagnosis and symptomatic treatment, to avoid delays in the condition.