North American family physicians and dietitians commonly recommend psyllium fibre supplementation for treating symptoms of irritable bowel syndrome (IBS). In this review, evidence on the effectiveness of psyllium supplementation for diagnosed IBS symptoms was evaluated and summarized. A systematic search of MEDLINE, CINAHL, and Web of Science was conducted. Included were full-length, peer-reviewed, English-language articles in which psyllium ingestion was tested for its effect on IBS symptoms. Quality of these articles also was assessed. Twelve met the criteria for complete data abstraction. Seventy-five percent of the studies examined were of weak quality. Study designs and methods were heterogeneous. Patient-perceived global symptoms improved significantly in six of the nine studies measuring a global symptom outcome. In one study, significant improvements occurred in reported abdominal pain; in three, improvement did not occur. Quality of life and flatulence did not improve significantly in any studies in which these outcomes were examined. The results of this systematic review indicate limited and conflicting evidence to support the recommendation of psyllium supplementation for symptomatic IBS treatment.