For thousands of years mankind has even used the roots of the cannabis (marijuana) plant for medicinal purposes. During the 1st century, Pliny the Elder described in Natural Histories that a decoction of the root in water could be used to relieve stiffness in the joints, gout, and related conditions.
By the 17th century, various herbalists were recommending cannabis root to treat inflammation, joint pain, gout, and other conditions. But since that time there has been very little research on the marijuana root and it’s medicinal potential.
Interestingly, the roots of cannabis do NOT contain THC, cannabidiol, or other known cannabinoids. Rather they contain a host of other apparently medicinal compounds, and the little research we have supports the historical and ethnobotanical claims of clinical effectiveness.
The full article is found here, in the Journal of Cannabis and Cannabinoid Research.