this work shows the pharmacological effect on the central nervous system induced by an alkaloid fraction obtained from valeriana pavonii . traditional medicine uses this specie in colombia for the same purpose of valeriana officinalis , although there are differences in their chemical structure, particularly in the presence of alkaloid compounds, fact that may imply important differences in their pharmacological and toxicological profiles. the alkaloid fraction displays anticonvulsant (maximal electroshock seizure) and antidepressant (behavioral despair test) like effects, more pronounced than those induced by the ethanolic extract. the fraction did not show the sedative effects elicited by the ethanolic extract, fact that could be due to another group of constituents, like flavonoids and terpenoids. these results support the etnobotanical use of this specie and the role that compounds of alkaloid type seem to play in the effects elicited on the central nervous system by valeriana pavonii .