The ethanolic extract (EE) of Acosmium subelegans (Mohlenbr) Yakovl (perobinha-do-campo) was tested to behavioral paradigms in mice to investigate its putative central depressant effect. Oral pretreatment with the EE significantly reduced in a dose-dependent way the locomotor activity and increased by 30-55% the barbiturate sleep duration relatively to control values. At the highest dose (1,0 g.kg-1) it decreased the extension time/flexion time ratio of the maximal electroshockinduced convulsions, enhanced the latency to the pentylenetetrazol-induced convulsions and diminished by 26% the number of seizures, indicating an anticonvulsant action. No changes were observed in the motor coordination, the core temperature, climbing behavior, catalepsy and the plus-maze performance. The preliminary results indicate that the EE of A. subelegans induce a CNS depressant effect, more specifically an anticonvulsant effect that deserve a thorough investigation.