Cannabis Oil produced and sold by "dealers" can have many contaminants and many times will have minimal amounts or no THC or CBD in them at all. Most of the time cannabis oil available on the street should be avoided for medicinal uses such as treating cancer. It's always better to make your own oil or to have someone you trust make your oil. This helps assure a very pure, high quality oil is obtained. If you know who made your oil, you can better know what you are getting in your oil.
Until 2017, products containing cannabidiol marketed for medical purposes were classed as medicines by the UK regulatory body, the Medicines and Healthcare products Regulatory Agency (MHRA) and could not be marketed without regulatory approval for the medical claims. As of 2018, cannabis oil is legal to possess, buy, and sell in the UK, providing the product does not contain more than 0.2% THC and is not advertised as providing a medicinal benefit.
Cannabidiol (CBD) is one of dozens of non-psychoactive cannabinoids found in the hemp plant. Cannabidiol, and all the other cannabinoids, were patented by the United States Government in 2003 as neuroprotectants and antioxidants (Patent No. 6,630,507). Cannabinoids are characterized by their ability to act on the cannabinoid receptors that are found throughout the body. CBD and other cannabinoids are naturally occurring compounds that display potent anti-inflammatory and pain-relieving properties. They can promote the body’s healthy regulation of the central nervous, immune, and endocannabinoid systems.