Medical marijuana, or medical cannabis, uses the cannabis plant or chemicals in it to treat symptoms or conditions. Medical marijuana mostly comes in the same forms as recreational marijuana, but there also are highly purified and lab-made versions used for certain conditions.
The cannabis plant contains more than 100 different chemicals called cannabinoids. Each one has a different effect on the body. Delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the main chemicals used in medicine. THC also produces the “high” people feel when they smoke marijuana or eat foods containing it.