The active ingredient in dulcolax is bisacodyl... it's the same thing. It is good, but very effective - take only 1 tablet, not 2 as it says on the pack -i'm speaking from experience! It works by drawing water into your bowels which then makes you go. I love it if i feel really uncomfortable as it's pretty quick but psyllium is my top choice now as it doesn't have the side effects (dulcolax gives me tummy cramps, not too bad, but not fun either).