What is THC (Tetrahydrocannabinol)? | Leaf Science | "THC is the primary ingredient in marijuana responsible f/the high. Marijuana is ID by its 2 active ingredients or chems: THC & CBD. THC is the psychoactive chemical that affects how you feel by creating the 'high.' But getting high is not all that it’s good for. THC has a wide range of medical benefits & is commonly rpted to relieve pain, nausea & depression, among other things." Click to read & share the full article.