It's common knowledge that your monthly period can be the cause of many discomforts, from mood swings to cramps. And it can also cause diarrhea.
The reason is still unknown, but it's thought progesterone or prostaglandin and how they cause the peristalsis muscles to contract could be the trigger.
Medication such as IMODIUM® Advanced can help treat your diarrhea, as well as associated symptoms such as cramps, gas or bloating.