Psyllium Husk (Isabgol) for Diarrhea Management

Research suggests that psyllium husk has antidiarrheal properties supported by a consistent body of evidence, including at least one randomized controlled trial from 1988 demonstrating that ispaghula combined with calcium significantly reduced stool frequency and improved stool consistency in chronic diarrhea patients. Studies indicate that multiple reviews spanning 2000 to 2025 corroborate these findings across various contexts, including IBS with diarrhea predominance and protease inhibitor-associated diarrhea in HIV patients, with proposed mechanisms centered on psyllium's gel-forming, water-holding capacity that appears to normalize stool form in both directions depending on need. A pharmacological study in animal models also found antisecretory and antidiarrheal activity at higher doses, lending some mechanistic support to the clinical observations, though this evidence is not directly transferable to humans. One mixed review introduces a note of caution, observing that fiber supplementation may exacerbate diarrhea in some individuals, and the overall evidence base relies heavily on narrative reviews and older trials rather than large-scale modern randomized controlled trials or meta-analyses, which represents a meaningful limitation when evaluating the strength of these conclusions.