Also known as marijuana and by numerous other names.It 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), tetrahydrocannabivarin (THCV).
The oldest known written record of cannabis use comes from the Chinese Emperor Shen Nung in 2727 B.C. Ancient Greeks and Romans were also familiar with cannabis, while in the Middle East, use spread throughout the Islamic empire to North Africa. In 1545 cannabis spread to the western hemisphere where Spaniards imported it to Chile for its use as fiber. In North America cannabis, in the form of hemp, was grown on many plantations for use in rope, clothing, and paper.