A methanolic extact of Gentiana lutea ssp. symphyandra roots has been investigated for its possible effects on the central nervous system of mice. At doses of 250 and 500 mg/kg (i.p.), the methanol extract of Gentiana roots caused a significant increase in the swimming endurance test and exhibited slight analgesic activity, but no lethality in mice suggesting some activity on the central nervous system. However, there was no indication of sedation or muscular fatigue at the doses employed. HPLC analysis showed that three secoiridoid compounds, gentiopicroside, swertiamarine and sweroside were present and may have been responsible for the CNS effects of the methanol extract of Gentiana lutea ssp. symphyandra roots.