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Cannabidiol (CBD) is a phytocannabinoid discovered in 1940. It is one of 113 identified cannabinoids in cannabis plants, along with tetrahydrocannabinol (THC), and accounts for up to 40% of the plant's extract.[13] As of 2019, clinical research on CBD included studies related to anxiety, cognition, movement disorders, and pain, but there is insufficient high-quality evidence that cannabidiol is effective for these conditions.[14][15] Nevertheless, CBD is an herbal dietary supplement promoted with unproven claims of particular therapeutic effects.[16] The global market size for CBD was predicted to exceed US$47 billion by 2028.[17]

Quick facts: Clinical data, Trade names, Other names, AHFS...
Clinical data
Trade namesEpidiolex, Epidyolex
Other namesCBD, cannabidiolum, (−)-cannabidiol[1]
License data
Routes of
Inhalation (smoking, vaping), buccal (aerosol spray),[3][4] oral (solution)[5][6]
Drug classHallucinogen (psychedelic); cannabinoid
ATC code
Legal status
Legal status
Pharmacokinetic data
Elimination half-life18–32 hours[12]
  • 2-[(1R,6R)-6-Isopropenyl-3-methylcyclohex-2-en-1-yl]-5-pentylbenzene-1,3-diol
CAS Number
PubChem CID
PDB ligand
CompTox Dashboard (EPA)
ECHA InfoCard100.215.986
Chemical and physical data
Molar mass314.469 g·mol−1
3D model (JSmol)
Melting point66 °C (151 °F)
Solubility in waterInsoluble
  • Oc1c(c(O)cc(c1)CCCCC)[C@@H]2\C=C(/CC[C@H]2\C(=C)C)C
  • InChI=1S/C21H30O2/c1-5-6-7-8-16-12-19(22)21(20(23)13-16)18-11-15(4)9-10-17(18)14(2)3/h11-13,17-18,22-23H,2,5-10H2,1,3-4H3/t17-,18+/m0/s1{PubChem}

Cannabidiol can be taken internally in multiple ways, including by inhaling cannabis smoke or vapor, oral, and as an aerosol spray into the cheek.[3][4] It may be supplied as CBD oil containing only CBD as the active ingredient (excluding tetrahydrocannabinol [THC] or terpenes), CBD-dominant hemp extract oil, capsules, dried cannabis, or prescription liquid solution.[6][15] CBD does not have the same psychoactivity as THC,[18][19] and will negate the psychoactive effects of THC on the body if both are present.[13][18][20][21] As of 2018, the mechanism of action for its biological effects had not been determined.[18][20] Unlike THC, which acts on the cannabinoid receptor type 1 (CB1) as a partial agonist, CBD instead is a negative allosteric modulator of CB1 receptors.[22]

In the United States, the cannabidiol drug Epidiolex was approved by the Food and Drug Administration in 2018 for the treatment of two epilepsy disorders.[23] While the 2018 United States Farm Bill removed hemp and hemp extracts (including CBD) from the Controlled Substances Act, the marketing and sale of CBD formulations for medical use or as an ingredient in dietary supplements or manufactured foods remains illegal under FDA regulation, as of 2021.[24][25]