RESUMO
Some labiatae family plants show antinociceptive activities. Melisa officinalis belongs to this family, thus, antinociceptive activity of the aqueous decoction and ethanolic maceration extracts of the aerial parts of this plant studied in mice. Antinociceptive activities were done using hotplate and writhing tests. In hot-plate and writhing tests, the intraperitoneal injection of both extracts showed significant antinociceptive activity in mice. Naloxone, an opioid antagonist, pre-treatment, inhibited the antinociceptive activity of the extracts in hot-plate test. The extracts exhibited antinociceptive activity against acetic acid induced writhing which was partially blocked by naloxone. It is concluded that the aqueous decoction and ethanolic maceration of the aerial parts of M. officinalis has antinociceptive effects and this may be mediated partially by opioid receptors