The gastric potential difference (PD) was measured in ten healthy volunteers after sodium taurocholate intake. This bile salt was given after treatment with dimethicone or placebo in a cross-over design study. With dimethicone the fall in PD was lower (16.1 vs. 24.8 mV,) and shorter (32.5 vs. 51.0 min) than with the placebo. Our result suggests that the silicone can prevent the formation of the gastric lesions induced by bile salts.