Disclosed are stemospironine salts of Formula 1: wherein HX represents HCl, HBr, L-tartaric acid, D-tartaric acid, sulfuric acid, (+)-(1S)-10-camphorsulfonic acid, ethanesulfonic acid and ethane-1,2-disulfonic acid. This invention also provides crystalline polymorph forms of the compound of Formula 1 wherein HX is HCl, stemospironine hydrochloride. This invention also provides a new crystalline form of the compound of Formula 2, stemospironine free base: Also disclosed are compositions containing one or more compounds of Formula 1, methods for controlling cough comprising administering a therapeutically effective amount of a compound of Formula 1, and methods for preparing compounds of Formula 1. Also disclosed is a method for preparing crystalline stemospironine hydrochloride polymorph Form II from stemospironine hydrochloride polymorph Form I.