Natural Remedies for Irritable Bowel Syndrome: A Comprehensive Review of Herbal-Based Therapies

TL;DR

This narrative review summarizes herbal and natural-product therapies for irritable bowel syndrome (IBS), emphasizing peppermint oil and Iberogast as the best-supported options and preclinical promise for curcumin, fennel oil, and cannabis derivatives. It concludes that most evidence remains limited by small, short, heterogeneous studies and calls for larger, long-term randomized trials.

Key findings

• IBS affects about 11% of people worldwide, with prevalence ranging from 1.1% in France and Iran to 35.5% in Mexico, and 35 million patients in the United States; the female–male ratio is 1.8–2:1.
• Peppermint oil and Iberogast (STW 5) have the strongest clinical support: a phase 3 trial in 69 Japanese patients using 187 mg peppermint oil improved patient global assessment, IBS symptom severity, stool frequency, and stool form; an observational study of 418 pediatric IBS patients (age 3–14 years) reported GI symptom score falling from 19.1 ± 8.9 to 4.8 ± 4.6 with 0.7% adverse events.
• Curcumin, fennel essential oil, and Cannabis sativa derivatives show preclinical anti-inflammatory, antispasmodic, or visceral-pain effects; a randomized trial of curcumin plus fennel essential oil (CU-FEO) in 121 mild-to-moderate IBS patients reduced abdominal pain and IBS-SSS after 30 days.
• Coffee evidence is mixed: a meta-analysis of >430,000 individuals found regular intake associated with lower likelihood of developing IBS (OR 0.84), but in diagnosed IBS patients coffee was linked to acute diarrhea and, in an Iranian study, weekly coffee increased IBS likelihood by 44% and high caffeine intake by 47%, with associations significant only in women (OR 1.48) and stronger in overweight/obese individuals (OR 1.72).

Methods

• Narrative/comprehensive review of herbal-based IBS therapies, covering peppermint oil, Iberogast (STW 5), curcumin, fennel essential oil, ginger, Aloe vera, Cannabis sativa, coffee, yellow gentian, and Chinese herbal medicine.
• Literature was searched in PubMed, Scopus, and Web of Science up to July 2025 using terms including “IBS,” “herbal remedies,” and specific herbal remedy names; the review synthesizes preclinical mechanisms, clinical evidence, and safety data rather than conducting a new primary study.

Limitations

• Stated by the paper: many studies have small sample sizes, short study durations, methodological weaknesses, heterogeneous designs, dosing regimens, and outcome measures; there is a lack of large-scale, long-term randomized controlled trials for most herbal remedies, limited evidence on herb–drug interactions and long-term safety, and most studies do not examine differential effects across IBS subtypes or patient subgroups.
• Stated by the paper: Chinese herbal medicines are often insufficiently characterized, limiting reproducibility; curcumin evidence comes mostly from studies with high risk of bias; and coffee studies are scarce, mostly observational, and heterogeneous, with no randomized clinical trials directly assessing coffee’s impact on IBS symptoms.
• Evident from the text: some remedies, such as yellow gentian, have no specific IBS studies reported, and several cannabis findings rely on preclinical models or small, uncontrolled, or unstratified human studies.