Physicians in the West were still bleeding patients to treat heart disease and many other conditions when a Persian physician and pharmacist wrote a medical text that would be considered forward-thinking by today’s standards. Mohammad Hossein Aghili Alavi Khorasani’s book examines the medicinal properties of almost two thousand drugs of natural origin (animal, mineral, plant). Written in 1772, it describes topical preparations that include the leaves, bark and flowers of the cannabis plant. Though he and other medical practitioners recognized the healing power of cannabis topicals hundreds of years ago, topicals fell out of favour in the 20th century and, along with other cannabis products, became illicit. Only now are they being rehabilitated in the eyes of the medical establishment. Topicals have no psychoactive effect Many lotions, balms, oils and sprays are now infused with cannabis compounds called cannabinoids. They bind to receptors in the endocannabinoid system, which helps regulate bodily functions and is tied to the nervous and immune systems. The cannabinoids Delta-9- tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) are used in various combinations to treat a wide range of conditions. These topicals bind to receptors near the skin and are not absorbed into the bloodstream. As a result they don’t cause psychoactivity and affect only the areas where they are applied. For that reason, a growing number of medical practitioners see them as a great way to relieve inflammation, muscle tension and pain such as that caused by arthritis, rheumatism and other conditions. In addition to having anti-inflammatory properties, topical applications of cannabinoids have anti-bacterial and immunity-modulating properties so they are sometimes used to treat burns, rashes, eczema, psoriasis and skin infections.