Medical marijuana dispensary. Cannabis (also known as marijuana) is an illicit drug containing the psychoactive chemical tetrahydrocannabinol (THC). Cannabis is useful medically due to its ability to relieve pain, increase appetite and control muscle spasms. Cannabis has the potential to treat the side-effects of chemotherapy and the symptoms of conditions including AIDS, multiple sclerosis and chronic pain from nerve damage. In the USA, the use of cannabis for medical purposes was first legalised in California in 1996, and by 2016 a majority of states permitted medical cannabis in some form. The two jars shown here contain the varieties NYC Sour Diesel (top) and Donkey Butter (bottom). Photographed on 1 February 2019, in the Greenhouse medical marijuana dispensary in Walled Lake, Michigan, USA.