Table 3.

Peppermint Oil (PMO) Effect on Human Small Bowel Physiology and Transit Time

Reference	Population	Methods	Findings
Wildgrube (1988)56	Adult IBS patients (n=40)	Enteric coated PMO vs. placebo × 2 weeks Oro-cecal transit (lactulose 3-hr breath hydrogen) Total GI transit time (Carmine red)	Oro-cecal transit increased from 43 to 86 min. vs. placebo 56 to 64 (P<0.05) Whole intestinal transit time increased from 39.0 to 46.5 hr. vs. placebo 8 to 8 (P<0.05) No change in stool frequency Decreased breath hydrogen production from 17,005 to 12,718 ppm/3 hr. vs placebo 13,908 to 11,820 (P<0.05)
Micklefield (2000)49	Healthy adults (n=6)	Gastroduodenal manometry to measure migrating motor complex Enteric vs. non-enteric coated PMO (90 mg) combined with caraway oil (50 mg)	Increase in duodenal contractions with enteric- vs. non-enteric coated capsules
Goerg(2003)53	Healthy volunteers (n=12)	90 mg PMO (0.1 mL) or 50 mg caraway oil vs. placebo vs. 10 mg cisapride vs. 10 mg butylscopolamine given in randomized order with 2-day washout Lactulose breath test (10 mL)	Prolonged orocecal transit time with PMO vs. placebo (85.0 ± 7.8 min vs. 65.0 ± 6.1, P=0.004) based on 15 ppm over baseline value
Micklefield (2003)51	Healthy volunteers (n=24)	Gastroduodenal manometry to study intra-duodenal PMO: 90 mg and caraway oil	During Phase I and II: No PMO effect on the duodenum During Phase III: PMO decreased frequency of contractions (particularly within the duodenum)
Mizuno (2006)44	Adult patients undergoing upper double contrast barium study (n=420)	Nonrandomized, (n=205) given PMO: 10 mL of 1.6% solution and (n=215) given water Degree of spasm and contrast filling of distal duodenal loops of duodenum blindly scored (0-3 range, indicating none to severe)	Less duodenal spasms in PMO group vs. Controls: 0.96 ± 0.05 vs 1.47 ± 0.0 (P<0.001) PMO inhibited barium flow to distal duodenum (P<0.001)

Unless otherwise indicated data is presented as mean ± standard deviation.