Sonographic measurement of gallbladder volume has allowed us to assay the influence of many substances (hormones, drugs, etc.) on gallbladder kinetics playing a pivotal role in digestive mechanisms. The aim of the present study has been to evaluate the effect of an alkaline bicarbonate water (Donata) on gallbladder emptying. The study was performed in cross-over. Ten healthy volunteers randomly assumed alkaline bicarbonate water or saline (400 ml). Gallbladder volumes were measured by ultrasonography, according to ellipsoid method, before and 15', 30', 45', 60', 90', 120' after water or saline intake. A week later the test was repeated. Gallbladder kinetics was evaluated referring to fasting volume, residual volume, absolute emptying and maximum percent emptied. Student's "t" test for paired data was used for statistical evaluation of the results. Gallbladder volumes were significantly reduced 15', 30', 45' and 60' after alkaline bicarbonate water administration, whereas saline did not induced gallbladder emptying. The present results suggest that Donata water may be employed in order to ameliorate dyspepsia due to biliary dyskinesia, moreover it may play a complementary role in the prevention and in the medical treatment of biliary lithiasis.