The main reasons for clean and fresh blood after 20 days postpartum are improper diet, puerperal infection, poor uterine rejuvenation, uterine cavity residue, cervical opening lacerations, etc. In this case, the patient should go to the hospital in time for gynecological, ultrasound, blood and urine HCG examinations to make a clear diagnosis and then carry out reasonable treatment. Common causes and treatments 1, improper diet: If the mother is overly tonic after delivery, such as eating a lot of chicken, beef, ginseng, abalone, etc., there may be a situation where bright red blood appears again after the dew is clean. After delivery, women should pay attention to a balanced diet and eat a light diet rich in high quality protein, nutritious and easy to digest; 2. Poor uterine regeneration: it can be characterized by weak contractions, a general feeling of abdominal cramping, long duration of bloody dew and a large amount of blood, and there may be fresh blood after the dew is clean. In case of poor uterine regeneration, you can use contraction agents and antibiotics to prevent infection under the guidance of a doctor. The commonly used drugs are ergometrine, contractin, penicillin, etc.; 3. Under the guidance of the doctor, apply broad-spectrum high-efficiency antibiotics, such as penicillin, ampicillin and other symptomatic treatment; 4, uterine cavity residue: if there is residual material in the uterine cavity, such as placenta, fetal membranes, blood clots residue, etc., can appear 20 days after childbirth and then flow of bright red blood after clean dew. In this case, you should go to the hospital for ultrasound examination in time to clarify the details of the residual material. If the residual material is small, you can use medicines such as motherwort granules and new biochemical granules under the guidance of the doctor to promote the discharge of residual material. For women with partial placenta residue or most of the fetal membrane residue, scraping should be performed to avoid the spread of infection; 5. Cervical opening laceration: If the woman is in normal labor, resulting in cervical opening laceration, the cervix has not recovered well after delivery, i.e., the symptom of fresh blood flowing again after clean malaria may occur. It is recommended to go to the hospital for gynecological examination to check if there is any infection at the wound and to treat it symptomatically. If the cervical opening laceration is more serious and the bleeding is more, the treatment of suturing to stop the bleeding should be carried out; 6, cervical polyps: If the mother has cervical polyps, irregular vaginal bleeding can occur, that is, after the malodex is clean, there may be fresh blood flowing again, usually polypectomy can be used for treatment.