Cannabis drugs are obtainable from the flowing tops or leaves of the plant.
The resin of C. sativa is often referred to as hashish and its constituents include cannabidiol, cannabinol and several tetrahydrocannabinols referred to collectively as T.H.C. Other constituents are cannabigerol, cannabichromene and cannabidiolic acid. The active principles are T.H.C., two of them. D l and D 6 T.H.C., being of great potency. The relations between the constituents and the possibilities of interconversion between some of them under different conditions such as the high temperature and degree of oxygenation that occur during smoking have been studied but are not as yet fully elucidated. Work is hindered by the relative insolubility of these substances.