Dextromethorphan, an antitussive agent

The title compound, 4‐meth­oxy‐12‐meth­yl‐12‐aza­tetra­cyclo­[9.31,10.02,7]hepta­deca‐2(7),3,5‐triene, C18H25NO, has a T‐shaped configuration, with the benzene ring (A) and the fused carbocyclic ring (C) forming the upright stock; the other carbocyclic ring (D) and the piperidine ring (E) are in the arm positions. Rings C, D and E have sofa, chair and chair conformations, respectively. In the crystal packing, the mol­ecules are joined through C—H⋯O hydrogen bonding into chains running along the c axis.