Cannabis is the most commonly used controlled drug in the UK. It is a plant that contains hundreds of different compounds called cannabinoids. The main psychoactive cannabinoid is called THC (tetrahydrocannabinol). Other cannabinoids in the cannabis plant include CBD (cannabidiol), CBG (cannabigerol) and CBN (cannabinol).  Plants are grown to contain different cannabinoid concentrations and can therefore produce different effects. Cannabis plants have been a part of human history for thousands of years. The plant material can be used for rope and fibres in addition to being used for medicinal, psychoactive and religious purposes. Laws controlling the use of cannabis emerged as early as the 14th century. The way that cannabis is legally controlled varies around the world. Some countries enforce strict laws that prohibit the minor possession of cannabis, some provide cannabis for medicinal use, and others offer cannabis for sale to the public to use recreationally, in a similar way to the sale of alcohol. All drug use has risks. This booklet is for information only and does not constitute or replace medical advice. If you have medical concerns about your drug use, please speak to a medical professional