Epilobium parviflorum Schreb. (Onagraceae) is used for the treatment of benign prostatic hyperplasia (BPH), but its biological action is not entirely identified. This paper aims to report data on E. parviflorum with respect to its antioxidant and antiinflammatory effects. The aqueous acetone extract of E. parviflorum showed higher antioxidant effect in the DPPH assay than well known antioxidants and inhibited the lipid peroxidation determined by the TBA assay (IC50 = 2.37 ± 0.12 mg/mL). In concentrations of 0.2–15.0 µg/mL the extract possessed a protective effect, comparable to catalase (250 IU/mL), against oxidative damage, generated in fibroblast cells. In the COX inhibition assay E. parviflorum decreased the PGE2 release, so showing inhibition of the COX-enzyme (IC50 = 1.4 ± 0.1 µg/mL). Copyright © 2008 John Wiley & Sons, Ltd.