Over 80 chemicals, known as cannabinoids, have been found in the Cannabis sativa plant. Delta-9-tetrahydrocannabinol (THC) is the most famous ingredient in cannabis. But CBD is obtained from hemp, a form of the Cannabis sativa plant that only contains small amounts of THC. CBD seems to have effects on some chemicals in the brain, but these are different than the effects of THC.
A prescription form of CBD is used for seizure disorder (epilepsy). CBD is also used for anxiety, pain, a muscle disorder called dystonia, Parkinson disease, Crohn disease, and many other conditions, but there is no good scientific evidence to support these uses.