The first thing you should do is to distinguish and see what is causing the diarrhea during menstruation. It is easy to cause slow gastrointestinal motility and indigestion during menstruation. If you eat too greasy food, it will cause indigestion diarrhea. You need to take medication to help digestion, you can take lactasepsin or bifidobacteria. If the diarrhea is severe, it can be treated with Montelukast. However, if you eat spoiled food, or raw and cold fruits and vegetables, and do not wash them well, it may be caused by inflammation and infection, and need to be treated with anti-inflammatory drugs. If you are breastfeeding, you need to take medicines that do not affect your baby’s breastfeeding, such as cephalosporin or amoxicillin, or you can take Flavopiridol Hydrochloride for anti-inflammation to control the inflammation. If you are not breastfeeding, you can take anti-inflammatory drugs such as norfloxacin and ofloxacin.