The appearance of blood again after three days of clean menstruation may be caused by menstrual disorders, cervicitis or cervical cancer. Close observation, treatment with ceftriaxone and surgery are needed. 1. Irregular menstruation: If a woman’s menstruation is clean for three days and there is blood again, it is very likely to be a manifestation of irregular menstruation. In addition to irregular menstruation, there can also be dysmenorrhea, menstrual bleeding and other manifestations, when women should actively adjust their lifestyle, calm their mind and relax properly. Regularly observe the phenomenon of vaginal bleeding. 2. Cervicitis: If there is blood after three days of clean menstruation, there may be a small amount of cervical bleeding caused by cervical inflammation. At this time, you can use ceftriaxone and other antibiotics for treatment, and also pay attention to keep the vulva clean. 3. Cervical cancer: If there is blood three days after menstruation is clean. And the bleeding occurs after coitus or transvaginal operation, you need to be alert to the occurrence of cervical cancer. Because cervical cancer will show contact vaginal bleeding. You can go to the hospital for cervical cancer screening, and after clear diagnosis, you can actively undergo surgical treatment, together with radiotherapy and other treatments. Ceftriaxone may cause diarrhea, rash and other adverse reactions, and should be used under the guidance of a doctor. If a woman’s period is clean for three days and then there is blood, and accompanied by other uncomfortable symptoms, you need to go to the hospital in time to see a doctor. Improve the examination to clarify the cause of the disease, and then under the guidance of the doctor for treatment.