Tooth bleeding for no reason requires oral examination and X-ray, the main cases are as follows: 1, if the crown is missing in a large area and is not repaired in time, soft tissues such as gums will penetrate deep into the cavity to form polyps, causing bleeding when brushing and eating; 2, the pulp cavity or root canal opening of the residual root or crown is open, the pulp forms pulp polyps under bacterial chronic infection, chewing will bite the polyps to cause breakage, causing massive bleeding; 3, the large pieces of calculus attached to the tooth surface will press and stimulate the gums, causing massive capillary hyperplasia and increased brittleness, the gums will ooze blood when the patient sucks or bites food.