Fenugreek (Trigonella foenum-graecum) is a plant whose seeds and fiber content have been traditionally used for various digestive issues, but there is also some scientific investigation into its effects on Irritable Bowel Syndrome (IBS). The primary rationale for its use is due to its high soluble fiber content, which can help regulate bowel movements and improve stool consistency. Soluble fiber has been shown in multiple studies to benefit IBS patients, particularly those with constipation-predominant symptoms, by increasing stool bulk and frequency.

There are a few small-scale clinical studies that specifically evaluated fenugreek fiber in IBS. For example, a double-blind, randomized, placebo-controlled trial published in the "Journal of the Association of Physicians of India" (1991) reported that fenugreek fiber supplementation led to improvements in abdominal discomfort and stool consistency in IBS patients. Other pilot studies and traditional usage reports support these findings, but sample sizes are small and methodologies are often not rigorous.

Overall, while there is some scientific evidence supporting the use of fenugreek fiber for IBS—primarily by leveraging the broader evidence base for soluble fiber—the data specific to fenugreek are limited. Therefore, the evidence is rated as modest (2/5), and more high-quality, large-scale studies are needed to establish its efficacy with confidence.