Background. Investigations into the medicinal properties of “Omonkhona” mineral water used for the treatment of hepatobiliary pathology make up the entirely new field of balneological research in Uzbekistan. Aims. The objective of the present study was to identify the hepatoprotective and choleretic components of the «Omonkhona» mineral water and elucidate their action in the patients presenting with the diseases of the hepatobiliary system. Materials and methods. A total of 77 patients suffering from the diseases of the hepatobiliary system were available for the examination including 38 patients with chronic hepatitis (CH), 17 with chronic cholecystitis (CC), and 22 patients with liver cirrhosis (Cr). All the patient were prescribed drinking the mineral water (from 1.0 to 3.0 liters per day) during consequtive 12—14 days. The clinical, biochemical, and instrumental studies were carried before and after the treatment. Results. The treatment with «Omonkhona» water resulted either in the complete elimination or the significant alleviation of pain in the right hypochondrium. The patients presenting with CH and CC experienced normalization of ESR even though it remained high in the Cr patients. All the patients exhibited a decrease of specific gravity of the urine, probably due to the diuretic effect of the mineral water. The biochemical studies of blood and bile showed that the initially slightly enhanced bilirubin levels, alanine aminotransferase and alkaline phosphatase activities in the CH and CC patients normalized after a course of the treatment with «Omonkhona» mineral water (p<0.05). No such changes were documented in the patients with liver cirrhosis. The patients with CH and CC experienced the two-fold reduction in the intensity of inflammation whereas the bilirubin and bile acid levels increased although the relative cholesterol content decreased and the cholate-cholesterol coefficient increased (p<0.05). The Cr patients demonstrated only insignificant changes of these parameters. The ultrasound examination showed that the CC patients treated with «Omonkhona» mineral water had a decrease in the swelling of the gallbladder walls, the improvement of its motor function and the disappearance of the stagnation phenomenon. In the CH patients, there was a significant decrease in the cranio-caudal size of the right lobe of the liver, the cranio-caudal size of the left lobe, and the anteroposterior size of the left lobe (p<0.05). A decrease in the acoustic conductivity was noted that can probably be attributed to the reduced swelling of the liver parenchyma. The Cr patients had no significant changes of these parameters following the treatment. Conclusions. The results of this study give evidence that the treatment of the diseases of the hepatobiliary system with “Omonkhona” mineral water exerts the well apparent positive influence on the patients presenting with CC and CH even though its beneficial effect was less pronounced in the patients with livre cirrhosis.