Effect of bisacodyl on ascending colon emptying t1/2 and on overall colonic transit at 24 hours. The bisacodyl group had significantly accelerated ascending colon emptying compared to the placebo group (p=0.03). Note that, in response to placebo, the progression from ascending colon to overall transit at 24 hours is highly variable; in contrast, there is a consistent progression for ascending colon to overall colonic transit in the bisacodyl group in all but three participants. Thus, although overall colonic geometric center was not significant in bisacodyl vs. placebo (p=0.19), 9 of the 12 participants appear to show substantial progression from ascending to overall colonic transit.