tetrahydrocannabinol (THC) /-hi′drōkənab′inol/ , the active principle, occurring as two psychotomimetic isomers, in the hemp plant Cannabis sativa, used in the preparation of marijuana, hashish, bhang, and ganja. THC increases pulse rate and has variable effects on blood pressure. It causes conjunctival reddening and a feeling of euphoria. The drug affects memory, cognition, and the sensorium; decreases motor coordination; and increases appetite. Nonintoxicating doses of THC are used experimentally in the treatment of glaucoma and to relieve nausea and increase the appetite in patients receiving cancer chemotherapy. See also cannabis.
