It is normal to have a slight fishy smell of blood during menstruation, which is normal, as long as you change your sanitary napkin and pay attention to the cleanliness of your perineum. However, if the menstruation is accompanied by obvious fishy smell, it indicates the possibility of pathogenic infection, possibly endometritis, endometrial polyps or malignant lesions of the cervix, etc. It is necessary to go to the hospital for examination and treatment according to the diagnosis. Endometritis can be treated with antibiotics, after anti-inflammatory treatment menstrual fishy smell will automatically ease, endometrial polyps caused by inflammation can be removed through hysteroscopic non-invasive surgery polyps and then do anti-inflammatory treatment. If you are suffering from malignant lesions of the cervix, which can lead to increased discharge and menstruation with a distinct foul odor, the best treatment is surgical excision and radiotherapy or chemotherapy according to your specific body condition.