In the title mol-ecular salt [systematic name: (5α,6α)-7,8-didehydro-4,5-ep-oxy-17-methyl-morphinan-3,6-diol hydro-chloride], C17H20NO3(+)·Cl(-), the conformation of the morphinium ion is in agreement with the characteristics of the previously reported morphine forms [for example, Gylbert (1973 ▶). Acta Cryst. B29, 1630-1635]. In the crystal, the cations and chloride anions are linked into a helical chain propagating parallel to the b-axis direction by N-H⋯Cl and O-H⋯Cl hydrogen bonds. The title salt and the morphine monohydrate [Bye (1976 ▶) Acta Chem. Scand.30, 549-554] display very similar one-dimensional packing modes of their morphine components.