Multicenter phase II randomized study evaluating dose-response of antiperistaltic effect of L-menthol sprayed onto the gastric mucosa for upper gastrointestinal endoscopy.

Aim: Peppermint oil solution was found to be effective for reducing gastric spasm during upper gastrointestinal endoscopy. The aim of the present study was to assess whether the gastric peristalsis-suppressing effect is dose-dependently induced by L-menthol, the major constituent of peppermint oil, and to determine the recommended dose of an L-menthol preparation.

Methods: In this phase II, multicenter, double-blind, dose-response study, 131 eligible patients were randomly assigned to receive 20 mL of 0.