Cannabis, also known as marijuana and by numerous other names, is a preparation of the Cannabis plant intended for use as a psychoactive drug or medicine. The main psychoactive part of cannabis is tetrahydrocannabinol (THC); it is one of 483 known compounds in the plant, including at least 84 other cannabinoids, such as cannabidiol (CBD), cannabinol (CBN), and tetrahydrocannabivarin(THCV).

Cannabis consists of the dried flowers and subtending leaves and stems of the female Cannabis plant. This is the most widely consumed form, containing 3% to 20% THC, with reports of up-to 33% THC. In contrast, cannabis varieties used to produce industrial hemp contain less than 1% THC and are thus not valued for recreational or medicinal use.

This is the stock material from which all other preparations are derived. It is noted that cannabis or its extracts must be sufficiently heated or dehydrated to cause decarboxylation of its most abundant cannabinoid, tetrahydrocannabinolic acid (THCA), into psychoactive THC.