There are over 100 active compounds contained in Cannabis plants, with cannabinoids and terpenes being the two largest groups. Two cannabinoids are the most significant of these compounds:

• tetrahydrocannabinol (THC), the main psychoactive substance in cannabis which is responsible its euphoric effects;
• cannabidiol (CBD) which produces the calming effects.

It is the terpenes in Cannabis which are responsible for its strong smell.

In the United Kingdom THC and other cannabinoids are deemed controlled substances under the MDA 1971, while CBD is not deemed to be a controlled substance.

The Cannabis market has four distinct categories:

1. Medical Cannabis – products derived or based on Cannabis plants and taken by patients as directed by a medical practitioner for the treatment of specific diseases or conditions such as epilepsy and multiple sclerosis;
2. Pharmaceutical Cannabis – medical products formulated using pure cannabinoids either derived from plants or synthetically created, which have obtained full clinical approval as pharmaceuticals;
3. Recreational cannabis – Cannabis used for non-medical purposes and obtained via illicit sources due to its illegality in many countries including the UK.
4. CBD wellness – a wide range of consumer products based on Hemp-derived CBD oils which do not contain any controlled substances and are consequently regulated as food supplements;

In addition to the Cannabis market, there is also a substantial Hemp industry which has four main product groups; fibres, shivs, pharmaceuticals and seeds.