An antitussive, which can be used for therapy or prophylaxis of coughing, is disclosed. The antitussive comprises as an effective ingredient a morphinan derivative having a nitrogen-containing cyclic substituent or a pharmaceutically acceptable acid addition salt thereof, having a specific structure, such as the compound below [N-(17-cyclopeopylmethyl-4,5α-epoxy-3,14-dihydroxy-morphinan-6β-yl)-3,4,5,6-tetrahydrophthalimide]. The antitussive has an excellent therapeutic or prophylactic effect against coughing and the side effects thereof are small.
