The plant is said to be a gateway drug, but this is simply incorrect. In an article that Dave Levitan wrote, he explains:
The “gateway hypothesis” or theory refers to the idea that one substance — marijuana, in this case — leads users to subsequently use and/or abuse other drugs… Though studies of large populations of people have indeed found that those who smoke marijuana are more likely to use other drugs, these studies show a correlation without showing causation — a commonly misunderstood phenomenon in science. In short, just became marijuana smokers might be more likely to later use, say, cocaine, does not imply that using marijuana causes one to use cocaine.