Peppermint oil (PO) was found to be safe and effective in treating pain and global symptoms associated with irritable bowel syndrome (IBS) in adult patients, according to the results of a recently published systematic review and meta-analysis.

In order to evaluate the effect of PO in the treatment of IBS, the authors reviewed abstracts of randomized controlled trials that compared enteric-coated PO to placebo in adult patients with IBS, diagnosed using Manning or Rome I, II, III, IV diagnostic criteria. Eligible studies were appraised using the Cochrane risk of bias tool. The primary outcomes included the proportion of patients with global symptom improvement and improved abdominal pain.

Twelve studies, with a total of 835 patients, met inclusion criteria and underwent systematic review and data analysis. The study authors reported, “For global symptom improvement, the risk ratio (RR) from 7 RCTs for the effect of PO (N=253) vs placebo (N=254) on global symptoms was 2.39 [95% confidence interval (CI): 1.93 to 2.97], I2=0%, z=7.93 (P<.00001).”

When assessing abdominal pain from 6 RCTs, the risk ratio for the effect of PO (N=278) compared with placebo (N=278) was reported as 1.78 (95% CI: 1.43, 2.20), I2=0%, z=5.23 (P<.00001). “The number needed to treat with PO to prevent 1 patient from having persistent symptoms was 3 for global symptoms and 4 for abdominal pain,” the study authors added.

Results of the study also found PO to be relatively safe. Data analysis of 8 RCTs found that 9.3% of PO patients reported adverse effects (32 events, 344 total) compared with 6.1% of placebo patients (20 events, 327 total) (RR: 1.40; 95% CI: 0.87 to 2.26; I2=0%, z=1.39; P=.16).

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“The strength of our findings is reflected by the large effect size of PO over placebo in the improvement of abdominal pain and global symptoms and by the low heterogeneity across included studies,” the authors concluded.


Alammar N, Wang L, Saberi B, Nanavati J, Holtmann G, Shinohara RT, Mullin GE. The impact of peppermint oil on the irritable bowel syndrome: a meta-analysis of the pooled clinical data. BMC Complementary and Alternative Medicine, 2019. DOI: