Petiveria alliacea L. (Phytolaccaceae) is an Amazonian shrub used in traditional medicine for many purposes. This study investigated the genotoxicity of the hydroalcoholic extract of P. alliacea (EHPa). In addition, we conducted pharmacognostic characterization and phytochemical investigation. Phytochemical screening and thin layer chromatography (TLC) were used to determine the chemical composition of the extract. Genotoxicity was evaluated using an in vitro comet assay in human lymphocytes (50, 100, and 250 mg/ml) and an in vivo micronucleus assay in mice orally treated with the extract (50, 100, and 250 mg/kg b.w., p.o.). The phytochemical screening identified the metabolites reducing sugars, alkaloids and saponins. TLC analyses identified organosulfur compounds in EHPa. Comet assay data showed that EHPa induced exacerbated DNA damage at 100 mg/ml treatments (EHPa 100 mg/ml: