In this study the antioxidant activity of forty-six methanol plant extracts, from the botanical families Asteraceae, Euphorbiaceae, Melastomataceae, Rubiaceae and Solanaceae, collected at the Regional Natural Park Ucumarí (RNPU, Risaralda, Colombia), were established by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay. The plant extracts that showed the greatest antioxidant activity were Phyllanthus sp. (54.0%, Euphorbiaceae), followed by the two species belonging to the Melastomataceae family Tibouchina grossa (47.0%) and Miconia lehmannii Cogn. (45.3%) and continuing with Lycianthes radiata (Sendt.) Bitter. (41.5%, Solanaceae). This is the first report on the antioxidant activity of these Colombian species.