Objective: To evaluate the free radical scavenging and cytotoxic activities of the butanolic (BuOH) extract, methanolic (MeOH) extract and 20-hydroxyecdysone extracted from the roots of Pfaffia glomerata. Materials and methods: Pfaffia glomerata roots were collected, powdered and extracted with methanol by maceration at room temperature. The extract was concentrated under vacuum, yielding a residue, followed by a butanol extraction. The 20-hydroxyecdysone (EC) was obtained by chromatographic separation of the BuOH fraction. An amount of 10 mg of each dry extract and EC was dissolved in 0.1% dimethyl sulphoxide-phosphatebuffered-saline solution (DMSO-PBS) and screened for their capabilities on scavenging thiobarbiturate reactive substances (TBARS). The antioxidant activity of each extract was determined in vitro by measuring malonyldialdehyde (MDA) and 4-hydroxynonenal (4-HNE) in erythrocyte ghosts treated with ferric-ascorbate. The investigation has also included the cytotoxicity measurement by Trypan blue exclusion test and tetrazolium reduction assay in mice peritoneal macrophages. Results: The free radical scavenging activity of EC was higher than that present in the BuOH fraction. The MeOH extract showed a remarkable pro-oxidant activity. The ECfree radical reaction-inhibition was almost twice of that of the control α-Tocopherol (αT). The Trypan blue exclusion assay confirmed toxicity of the MeOH extract, whose lethality surpassed 80% of the treated macrophages after 1 h of 0.01 mg exposure per 10 6 cells.Conclusions: The present study shows the antioxidant effect of the Brazilian Ginseng. The scavenging effect was evidenced for EC as well the BuOH fraction. The MeOH extract showed cytotoxicity on mice peritoneal macrophages. Such toxicity is probably due to ginsenosides present in this latter fraction and warrants further toxicological evaluation of the Brazilian Ginseng roots.