What is THC? Home › Forums › What is THC? This topic has 3 replies, 3 voices, and was last updated 4 years, 7 months ago by Danielle. Viewing 1 post (of 1 total) Author Posts February 23, 2019 at 7:06 am #998 DanielleMember THC (tetrahydrocannabinol) is the part of the cannabis plant that produces a euphoric feeling because it is psychoactive, and interacts with brain chemistry. Author Posts Viewing 1 post (of 1 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In