Cannabis RSO (Rick Simpson Oil) is a concentrated form of cannabis extract that contains high levels of THC (tetrahydrocannabinol) and other beneficial compounds found in the cannabis plant. RSO is typically made by extracting the active compounds from cannabis flowers using a solvent, such as ethanol or butane. The extraction process results in a thick, dark oil that is rich in cannabinoids like THC, CBD (cannabidiol), and others.