Hi Elaine. Your menstrual cycle can certainly affect your bowel movements, causing cramping and loose stools. Treatment effects from alli usually occur as loose, oily stools. Was there oil in your stool that morning? Treatment effects are almost always caused by eating too much fat - the more fat you eat, the more treatment effects you get. It could be possible that the combination of getting your period with the alli may have caused it - but you say that you stopped the alli for a day and a half. Was that before you had the cramping and diarrhea? It is tough to pinpoint it for sure, other than to watch how your body reacts to the plan when you do not have your period. If you continue to handle it fine as you had before, and it happens again at your next menstruation, you know it was hormonal.
Hope this helps!
Maria Marzella Sulli, Pharm.D.