Polyethylene glycol 3350
"I have a colostomy bag and want to regulate my bowel so it doesn't act all by itself.  I take 2 capfuls each day (usually late afternoon or early evening) but regardless of the time at least before I go to bed.  Within 2 hours it works and clears out the colon so I don't have much action during the day when I am out and about>  Works Wonderful for my situation, with no pain or discomfort.  Have had my colostomy for 18 years and have been controlling things this way for about 5 years with no ill effects."