Cannabis, also known as marijuana among other names,[lower-alpha 1] is a psychoactive drug from the Cannabis plant used for medical or recreational purposes.[17][18][19] The main psychoactive part of cannabis is tetrahydrocannabinol (THC), one of the 483 known compounds in the plant,[20] including at least 65 other cannabinoids.[21] Cannabis can be used by smoking, vaporizing, within food, or as an extract.[6]