Marijuana is a mixture of the dried and shredded leaves, stems, seeds, and flowers of the cannabis sativa plant. The mixture can be green, brown, or gray.
A bunch of leaves seem harmless, right? But think again. Marijuana has a chemical in it called delta-9-tetrahydrocannabinol, better known as THC. A lot of other chemicals are found in marijuana, too—about 400 of them, many of which could affect your health. But THC is the main psychoactive (i.e., mind altering) ingredient. In fact, marijuana’s strength or potency is related to the amount of THC it contains. The THC content of marijuana has been increasing since the 1970s. Estimates from confiscated marijuana indicated that it contains almost 10 percent THC, on average.