What is CBD? Cannabidiol and current research

Author: Dipl.-Chem. Mohammad Reza Talebnasab
Editorially updated: 12 October 2026

What is CBD? The abbreviation stands for cannabidiol, a constituent of the cannabis plant. CBD is a cannabinoid, but it is distinct from THC. Research investigates its biological properties and possible medical applications. A reliable assessment must distinguish between the individual substance, the preparations studied and claims about commercially available CBD products.

CBD and THC: what is the difference?

THC is mainly responsible for the typical cannabis high. CBD, by contrast, is considered non-intoxicating. This does not mean that CBD is biologically inactive or inherently free of adverse effects. A product may also contain other ingredients alongside CBD. The properties of pure cannabidiol therefore cannot simply be extrapolated to every mixture. Health Canada: information about cannabinoids

How does CBD act in the body?

Cannabidiol affects various biological targets. It cannot accurately be described as a simple activator of all cannabinoid receptors. For example, a cell-based investigation showed negative allosteric modulation at the CB1 receptor: CBD altered the receptor's signalling response to other substances. Such a laboratory finding describes a possible mechanism but does not establish treatment success in humans. Experimental study of CBD and CB1

Our page on the endocannabinoid system, including CB1, CB2, anandamide and 2-AG explains the biological background.

CBD in medicine: what is authorised?

In the European Union, the prescription cannabidiol medicine Epidyolex is authorised as an add-on treatment for certain forms of epilepsy. These include Lennox–Gastaut syndrome and Dravet syndrome in conjunction with clobazam, and tuberous sclerosis complex. The authorisations cover patients aged two years and over; treatment requires specialist medical supervision. These clearly defined indications do not establish the general efficacy of commercially available CBD oils. European Medicines Agency: Epidyolex

CBD and pain: why studies need careful reading

Pain is a frequent subject of CBD research. However, positive findings for cannabis or THC–CBD combinations must not automatically be attributed to CBD alone. In a 2023 randomised study involving 86 people with knee osteoarthritis, CBD added to paracetamol provided no greater pain relief than placebo. Adverse events were more frequent. This finding applies to the preparation and study design investigated; it does not answer every question about other forms of pain. Clinical knee osteoarthritis study, 2023

Anxiety, mood and other research areas

A small study of 24 people with social anxiety disorder investigated CBD during a simulated public-speaking task. Some results were favourable, but a single experimental stress situation is not equivalent to long-term treatment. Neither a general recommendation for anxiety disorders nor an established antidepressant effect can be inferred. Experimental study of social anxiety, 2011

Inflammatory processes, neurological conditions and tumour biology are also being researched. The frequently cited study by Ligresti and colleagues investigated cannabinoids in tumour cells and animal models. It was not a clinical cancer treatment in patients. Such results are a starting point for further research, not evidence that a CBD product treats cancer. Ligresti et al., 2006

CBD: adverse effects and interactions

CBD can cause adverse effects, including sleepiness, diarrhoea, decreased appetite and changes in liver enzyme levels. Interactions with medicines are possible. Anyone taking medicines or living with a medical condition should discuss CBD-related questions with a doctor or pharmacist. ‘Natural’ and ‘non-intoxicating’ do not guarantee safety. NCCIH: benefits, risks and unresolved questions

CBD oil, extract and medicine are not the same

The term CBD oil alone does not describe a product's full composition or legal status. Relevant factors include the substances present, their concentrations, intended purpose and specific product category. An analytical report can make information about the tested composition traceable; it replaces neither marketing authorisation as a medicine nor clinical evidence of efficacy.

For an objective comparison, further introductory information is available on cannabigerol (CBG) and cannabinol (CBN). The history of cannabis places the plant in its historical context.

Note: this article provides general scientific information. It does not replace diagnosis, medical advice or treatment and contains no dosage or product-use recommendations.

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​Further reading: Cannabinoids and medicines: mechanisms and risks of interactions.

Product overviews: Full-spectrum CBD · Broad-spectrum CBD · Cannabinoid bundles.