THC Vials (IMAGE) University of New Mexico Caption Vials of THC, the notorious psychoactive chemical in cannabis, was found to be more important for therapeutic effects than previously believed. Credit UNM Usage Restrictions Please use credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.