Some Gentiana species have been used by the nomadic people of Siberia as bitter teas or appetizers to eliminate digestive disorders (dyspepsia, heartburn, nausea, etc.). We studied the most frequently used gentians: Gentiana algida, G. decumbens, G. macrophylla and G. triflora. The aim of the present study was to evaluate the phytochemical features and gastrostimulatnt activity of these four gentian herbs. Five iridoids, seven flavones and mangiferin were detected in gentian herbs after analysis by microcolumn-RP-HPLC-UV-ESI-MS. A componential phytochemical profile of the G. decumbens herb is presented for the first time, as well as information about distinct phytochemicals found in gentian herbs. HPLC quantification of the specific compounds of gentian herbs demonstrated the high content of iridoids (24.73–73.53 mg/g) and flavonoids (12.92–78.14 mg/g). The results of biological activity evaluation of four gentian decoctions demonstrated their good ability to stimulate acid-, enzyme- and mucin-forming functions of the stomach attributed to mostly by iridoids and flavonoids. In general, it can be claimed that the gentian decoctions can be used as effective and safe appetizers and are also a good source of biologically active agents.