The essential oil was obtained from leaves of Piper aduncum L. "matico" from in Department of Loreto by steam distillation with a yield of 1.1% v/w. The chemical composition has determined by chromatography/mass spectrometry (GC/MS). Thirty-five chemical components were identified, of which eight represent 76,53 % of the total area. The main volatile compounds are phenylpropanoids (1, 2, 4-trimethoxy-5- (1-propenyl) -benzene (39,32%) and methyleugenol (12,85%)), sesquiterpenoid hydrocarbons (germacrene D (7,52%), bicyclogermacrene (5,88%), β-caryophyllene (2,82%) and δ-cadinene (2,81%)), a monoterpenoid hydrocarbon (β-ocimene (2,34%)) and an oxygenated monoterpenoid (4,7,7-trimethylbicyclo [2.2.1] heptan-3-one (2,99%)). The antioxidant activity was evaluated by DPPH● and ABTS●+ radical scavenging methods. The antioxidant capacity equivalent to Trolox (TEAC-DPPH) (TEAC-ABTS) was 1....