Senna reticulata is a species belonging to the family Fabaceae; distributed in Colombia found its highest concentration in the departments of Tolima and Cundinamarca; It has traditionally been used as a laxative, diuretic, laxative and also for the treatment of constipation and fever. In terms of chemical composition studies they have reported the presence of flavonoids, alkaloids, tannins, saponins and anthraquinone. The main objective of this study was to contribute to the phytochemical study of the leaves of this species and assess their antioxidant activity. To this end, from plant material collected in the municipality of Honda (Tolima) and identified in the Colombian National Herbarium collection under number 573 012 COL ethanol extract (131.18 g) was obtained; which separations by column chromatography, and preparative thin layer yielded a mixture consisting of erythritol, isoamyl acetate and L-pyroglutamic acid and isolation of quercetin, kaempferol and hyperoside, first reported for this species in our country. The structural elucidation of the isolated compounds was carried out using techniques GC-MS and 1H NMR, 13C. The antioxidant activity is evaluated by the method of DPPH, where it was established that the presence of flavonoids and phenolic compounds, were responsible for the antioxidant activity presented for the ethanol extract, fractions of dichloromethane and ethyl acetate and kaempferol, a inhibition rate above 40% with reference to the uptake of gallic acid antioxidant free radical DPPH.