Animated light micrograph (LM) of THC (tetrahydrocannabinol) crystals. Tetrahydrocannabinol (THC) is the main psychoactive drug found in the hemp plant (Cannabis sativa). Its pharmacological actions are the result of its binding to specific cannabinoid receptors located in the brain and throughout the body. Effects include relaxation, euphoria, altered space-time perception, enhancement of visual, auditory, and olfactory senses, disorientation, and appetite stimulation. A number of studies indicate medical benefits for cancer and AIDS patients by increasing appetite and decreasing nausea. It has been shown to assist some glaucoma patients by reducing pressure within the eye, and is used by a number of multiple sclerosis patients for relieving spasm. Other studies indicate a variety of negative effects associated with constant, long-term use, including memory loss, depression and loss of motivation.