(HealthDay News) — For patients undergoing colonoscopy, L-menthol sprayed directly onto the colonic mucosa improves the adenoma detection rate, according to a study presented at the annual Digestive Disease Week, held from May 3 to 6 in Chicago.

Noting that L-menthol has suppressed gastric peristalsis in upper gastrointestinal endoscopy, Ken Inoue, MD, from the Kyoto Prefectural University of Medicine in Japan, and colleagues examined its efficacy by endoscopic spray in colonoscopy. 

Two hundred twenty-six patients were randomly assigned to receive 320 mg L-menthol (n=118) or placebo (n=108), which was directly sprayed on the cecum. If and when intestinal peristalsis occurred, L-menthol was sprayed again in the L-menthol group.

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The researchers found that in the L-menthol group, the adenoma detection rate was significantly higher than in the placebo group (60.2 vs. 42.6; P = 0.0083). In the L-menthol group, a significantly higher proportion of patients had no peristalsis after treatment, compared with the placebo group (71.2% vs. 30.9%; P < 0.0001). The peristaltic scores were significantly lower for L-menthol-treated patients than before treatment (P < 0.0001 after treatment). 

In the placebo group, the scores were not significantly different before and after treatment. No adverse effects were observed in either group.

“The results suggest that the suppression of colonic peristalsis by L-menthol sprayed directly onto the colonic mucosa improves the adenoma detection rate,” the researchers wrote.


  1. Inoue K, Dohi O, Gen Y, et al. 740 L-Menthol Sprayed Onto the Colonic Mucosa Increases Polyp Detection During Colonoscopy: a Prospective, Randomized Trial. Gastrointest Endosc. 2014;79(5):Supplement, Page AB170.