A chemical substance (
C21H20O2) which is produced by the hemp plant (Cannabis sativa), and is the physiologically active agent of dried preparations of that plant, called variously marijuana, hashish, ganja, hemp, etc.; also called
THC. It causes the euphoric effect for which the preparations are smoked or chewed. It is used in medicine in a purified form as an antiemetic (an antinausea agent), especially in conjunction with chemotherapy of cancer. It occurs primarily as the
1-3,4-trans isomer, also called 9-THC, with small amounts of the 6-3,4-trans isomer detectable at about 1%. It is a controlled substance, classified as a hallucinogen, and its possession or distribution is illegal in almost all states of the United States. [PJC]