Cannabidiol (CBD) is a naturally occurring cannabinoid constituent of cannabis. It was discovered in 1940 and initially thought not to be pharmaceutically active. It is one of at least 113 cannabinoids identified in hemp plants, accounting for up to 40% of the plant’s extract. It does not have intoxicating effects like those caused by THC, and may have an opposing effect on disordered thinking and anxiety.

Medical reviews published in 2017 and 2018 incorporating numerous clinical trials concluded that cannabidiol is an effective treatment for certain types of childhood epilepsy. The drug was approved by Canadian authorities in 2005 to alleviate pain associated with multiple sclerosis.