Rick Simpson Oil (RSO) is a concentrated cannabis extract with high levels of THC. Rick Simpson Oil is an ultra-concentrated crude cannabis oil. The oil is dark with a dense, thick consistency, closer to grease than oil. Rick Simpson’s website defines RSO as “extremely potent decarboxylated extract." RSO is considered a “whole-plant extract,” meaning it contains THC as well as other cannabinoids, flavonoids, and other plant molecules like waxes chlorophyll; however, RSO typically contains low terpene content due to how it is processed.