Psyllium, a soluble fiber derived from the husks of Plantago ovata seeds, has been investigated for its effects on Inflammatory Bowel Disorders (IBD), including ulcerative colitis and Crohn's disease. The rationale for its use is based on its capacity to form a gel-like substance when mixed with water, which can help normalize stool consistency and promote regularity. In the context of IBD, psyllium may support gut health by acting as a prebiotic, fostering beneficial bacteria, and producing short-chain fatty acids (such as butyrate) via fermentation—these metabolites are thought to have anti-inflammatory effects on the colonic mucosa.

Clinical trials have provided moderate evidence for the use of psyllium in IBD, particularly ulcerative colitis. For example, a small randomized trial (Hallert et al., Am J Clin Nutr, 1991) found that psyllium was as effective as mesalamine in maintaining remission in ulcerative colitis patients. Subsequent studies and systematic reviews have suggested that while psyllium may improve stool frequency and consistency, its effect on active inflammation is modest and data for Crohn's disease is less robust.

Overall, the evidence supporting psyllium’s use in IBD is moderate (score 3), mainly for symptom management and as adjunctive therapy for maintenance of remission in ulcerative colitis, rather than as a primary anti-inflammatory agent. Patients should consult their healthcare provider before initiating psyllium, as fiber supplementation may be contraindicated during active disease flares or if strictures are present.