There are several reasons for vomiting blood from the mouth: first, gum disease or periodontal disease caused by, in general, dental calculus plaque, stimulation of the gums will produce inflammation of the gums, there will be bleeding on the edge of the gums, when spitting water will appear bleeding phenomenon. Second, the mouth spitting blood may be caused by trauma in the mouth, such as trauma or a sudden bite wound, there will be the phenomenon of mouth spitting blood. Third, the mouth spitting blood may be produced after tooth extraction, if the gums are torn after tooth extraction, or the wound in the first two days there will be bleeding symptoms, there will be bleeding when spitting, this is a normal phenomenon, if necessary, bleeding larger amount should be stitched treatment. Fourth, the mouth spitting blood and possible bleeding is the mouth, throat inflammation, there will generally be mucosal rupture, there will also be bleeding phenomenon.