Tooth bleeding is actually gum bleeding, bleeding for many reasons: 1, may be due to dental caries, dental caries is due to food residue embedded in the teeth, a large number of bacterial reproduction caused by the invasion of the tooth body, stimulated by the phenomenon of gum bleeding. 2. Periodontitis, periodontitis is mainly caused by dental calculus, and plaque and so on, which is manifested as inflammation of gums, often easy to red, swollen, bleeding, capillary expansion, so when not paying attention, there will be gum bleeding. 3. It may be due to systemic blood diseases, such as hemophilia, and leukemia, etc. These diseases may have symptoms of bleeding gums. So the specific problem still needs to be observed, or go to the hospital for treatment.