Suggest Remedy For Chronic Diarrhea

my 91 y/o mother has had chronic diarrhea for months. she was in an alf for 7 months and was given her usual bland diet, as I have been doing, but the problem continues. I have tried Imodium but it only works for a short time. i m thinking maybe ibs because she goes immediately after a meal. my email is YYYY@YYYY -- I have a drs apt on Tuesday, but what do you suggest?