The Effects Of Marijuana Use Marijuana, good or bad? Some say good and some say bad. Here are three sides to the effects of marijuana usage. The plant Cannabis sativa is the source of marijuana, the leaves, flowers, and twigs are crushed to produce marijuana. The drug is usually smoked but sometimes eaten. Marijuana has different usage’s and different effects depending on how its used. First of all, in the early 1900’s Marijuana started to be used as a pleasure inducing drug and by the 1960’s and 70's its usage became wide spread among young adults making marijuana the second most popular drug after alcohol. Many users describe two phases of