Pracaxi, or Pehtaclethra macroloba (Willd.) Kuntze, Fabaceae-Mimosoideae, is a medicinal plant used in Brazil against snakebite, as healing and as insecticide. Its stem organic extract showed relevant cytotoxicity. Reports concerning alterations in behavioral phenotype are not known, nor were compounds isolated from pracaxi stem. Organic extract (EB827) were administered to Balb-c male mice and general behavioral changes related to motor, sensorial and central/autonomous nervous systems were evaluated. Both 50% lethal (LD50) and non-lethal doses (NLD) tendencies were determined. EB827 was chemically studied using partition, column chromatography and thin layer chromatography to isolate four compounds that were H1 and C13 nuclear magnetic resonance analyzed. LD50 tendency was 228.25 mg/mL for EB827 and NLD was 78.1 mg/mL. Impairment in general activity was observed, as it did in tail squeeze, response to touch, defecation, cyanosis and breath. Then, behavioral changes in general activity, response to touch, tail squeeze, defecation and breath were observed after NLD administration. Locomotion was diminished by the administration of EB827, as immobility time has increased, in the open field apparatus. Necropsy showed that mice ended up with pale liver and opaque internal organs, despite the occurrence of haemorrhage, which could have been the cause of amimals death. Friedelin, epifriedelanol, sitosterol and stigmasterol were isolated from pracaxi stem. Behavioral phenotype after administration of the organic extract of pracaxi was determined by the subsequent analyses proposed in the present work, and displays the basis of further pharmacological studies. Also, four molecules were described to occur in the stem of the plant for the first time.