Hydrogen sulfide medicinal waters of Tuva are represented mainly by thermal and cold springs and saline as and mud lakes. The presence of hydrogen sulfide in the springs, especially thermal, often accompanied by the development of blue-green algae. The therapeutic effect of hydrogen sulfide is associated with present in water free hydrogen sulfide, which has an active chemical properties.

In this article are used the results of the research of complex expedition of the Research Institute of Medical and Social Problems and Management of the Tuva Republic (these authors were members of the expedition) and the results of hydrochemical analyzes of Interuniversity Regional Environmental Research Laboratory of Irkutsk State University. Field work was conducted in the summer season of 2014 and 2015 in different regions of the Tuva Republic.

In our effort we used stipulated by PNDF 14.1:2:4.126-98 methods, according to which the characteristics of the determination of hydrogen sulphide in mineral waters are iodometric and titrometric. The a comparative analysis of literature and experimental data showed that in more than 40 years period the temperature, regime degree of mineralization, the ratio macrocomponental composition and content of reduced forms of sulfur in the water sources has not changed. This testifies to the constancy of hydrogen and chemical conditions of mineral waters formation.

The scientific and practical significance of the was research results represented in research reports of The Research Institute of Medical and Social Problems and Management of The Tuva Republic New data about mineral composition of the water sources wehe included in the database of the water’s condition monitoring of The Tuva Republic, on the basis of which it is planned to develop recommendations on the use of mineral water.