Having sex during menstruation can lead to the invasion of pathogenic bacteria that can cause inflammatory changes in the endometrium or cause inflammation of the pelvis. Sex during menstruation may also lead to endometriosis, causing infertility. So, don’t have sex during menstruation. If you do have sex during menstruation, you can take the following remedies: First, take 2 days of oral anti-inflammatory drugs, mainly to prevent infection caused by the invasion of pathogenic bacteria. Secondly, you can take hot brown sugar water orally for 2-3 days to make the menstrual blood flow out of the cervix more smoothly and avoid backflow of menstrual blood into the pelvis, which may cause endometriosis.