"There are over 400 chemicals in marijuana, but only 61 [80 as of July 9, 2009; see Editor's Note below] of them are unique to the Cannabis plant -- these are called cannabinoids. One of them, delta-9-tetrahydrocannabinol (THC), was isolated and synthesized in 1964 and is clearly the most pharmacologically active.
Take special note that the relationship of THC to Cannabis is probably more similar to the relationship of mescaline to peyote then of alcohol to beer, wine, or distilled spirits. Alcohol is the only behaviorally active agent in alcoholic beverages, but there might be several active agents in Cannabis."

You are confused.