The bioactivity-guided phytochemical investigation of the crude hydralcoholic extract of Nectandra megapotamica was carried out using the abdominal constriction test in mice, which led to the isolation of three active compounds: alpha-asarone (1), galgravin (2) and veraguensin (3). The crude extract (EBCA, 300 mg kg(-1)) and isolated compounds 1,2, and 3, at different doses, were evaluated using the acetic acid-induced abdominal constriction test in mice, carrageenan-induced paw oedema in rats, and hot plate tests in rats. The EBCA showed a significant effect in the abdominal constriction and hot plate tests, but did not show activity in the rat paw oedema assay. All isolated compounds displayed activity in the abdominal constriction test, but only compound 1 was active in the hot plate test. Compounds 2 and 3 displayed activity in the anti-inflammatory assay. It was suggested that the analgesic effects obtained for EBCA could be due mainly to the presence of its major compound, alpha-asarone (1).