Bleeding between the teeth indicates gingivitis or periodontitis, both of which are caused by poor oral hygiene. Gums around the long-term accumulation of tartar, plaque, food debris and soft tartar, these substances on the one hand, pressure on the gums will make the gums easy to bleed, on the other hand, it will also release toxins, resulting in redness and swelling of the gums, brittle texture, gums will bleed when eating and talking. Blood between the teeth may also be suffering from inflammation of the interdental papillae. Inflammation of the interdental papillae will also make the papillae bleed easily, and the cause of its formation is the same as that of periodontitis and gingivitis. The main treatment for these diseases is to thoroughly remove the dirt around the teeth, mainly using ultrasonic scaling to remove tartar, pigmentation and plaque in the periodontal pockets, on the tooth surface and between the teeth, as well as localized periodontal rinsing and medication, and applying iodine glycerin to the gingival papillae and periodontal pockets for localized anti-inflammatory treatment. After a series of treatments, the bleeding between the teeth will gradually ease until it disappears. Patients should also maintain oral hygiene at home, brush and rinse their teeth carefully, and go to the hospital regularly for ultrasonic cleaning treatment.