Vaginal blood may be caused by physiological factors such as menstruation or ovulation, or by pathological phenomena such as damage to the vaginal wall and gynecological inflammation. 1. Physiological reasons: a small amount of bleeding before and after menstruation can be manifested as blood, which will recover by itself after menstruation is clean; bleeding during ovulation is usually small in amount, which can also be manifested as blood in the vagina, which is a normal physiological phenomenon. 2. Pathological causes: the most common are vaginal wall injury and infectious diseases of the reproductive tract, such as vaginitis, endometritis, cervicitis and so on, which can lead to irregular vaginal bleeding. You should go to a regular hospital to find out the cause of the disease and treat the symptoms in time. It is recommended to pay attention to the cleanliness and hygiene of the private parts in daily life, keep them dry, change underwear every day and pay attention to the protection of the private parts, avoiding violent collision.