Comparative laxation of psyllium with and without senna in an ambulatory constipated population.

Our short-term study used objective and subjective criteria to evaluate the ability of two laxative preparations to relieve constipation. Forty-two adults who were constipated, i.e., had less than or equal to 3 bowel movements during 1 wk of a single-blind placebo treatment, were randomized to receive psyllium (7.2 g/day) or psyllium plus senna (6.5 + 1.5 g/day). Both laxatives increased defecation frequency and wet and dry stool weights although the added effect of the senna was clearly evident. Only the psyllium with senna increased stool moisture. Two distinct responses to the psyllium plus senna were evident; the subpopulation of high responders (n = 7) was responsible for most of the increase in stool frequency and dry weight in this group, and laxation in the subpopulation of normal responders (n = 12) was similar to that observed in those receiving psyllium alone. Both laxatives provided a similarly high degree of subjective relief and improvement in stool consistency. When constipation was assessed objectively by stool frequency and weight, laxation was attained by 63% of the psyllium plus senna group and 48% of the psyllium group.