Hi , My dad went through the colon cancer surgery/chemo/radiotherapy treatment about three years back. First year, he had the same issue where he had frequent bowl movements after he ate anything. Dr. asked to try IMODIUM OTC, which worked like a charm..but after all this time, the symptoms are back again and this time, Imodium ( or any other medications) is not helping. Can you please suggest what might be going wrong here.