Tetrahydrocannabinol (THC) has various effects on the body, both positive and negative. The positive effects include pain relief, relaxation, and an overall feeling of euphoria. Other positive effects of THC use include reducing anxiety and depression, reducing nausea and vomiting in chemotherapy, stimulating appetite in patients with AIDS or cancer, improving sleep and reducing seizures in epilepsy. The blog tetrahydrocannabinol.com has many useful facts about marijuana and its effects.