Active principle in hemp-plant derivatives such as marihuana, hashish, and ganja. Considered a mild hallucinogen, it causes sensory and perceptual disturbances, euphoria and other mood changes, decreased motor coordination, and various physiological changes, including alterations in pulse rate, respiration rate, and pupil size. THC is a drug of abuse but has also been used to relieve the nausea and vomiting associated with chemotherapy for cancer.
A chemical, C2iH30O2, that is the principal active component in cannabis, or marijuana.