Rick Simpson Oil (RSO) is a cannabis oil made from the flowers of the cannabis plant. It is named after its Canadian creator, Rick Simpson, who used it to treat his tinnitus and later used it to treat his skin cancer. RSO is made by washing cannabis buds with a solvent, such as pure light naphtha or grain alcohol, and then boiling off the solvent leaving behind the oil. The end product is a high potency oil often dark in color with a thick consistency. RSO can be taken orally, applied topically, or smoked, depending on preference. It is known to have a strong bitter flavor, so some people mix it with food or drinks to mask the taste. RSO contains high levels of THC and other cannabinoids, and it is illegal to buy in many places. However, in states that have legalized marijuana, RSO can be found at cannabis dispensaries. While some early studies suggest that THC may help control nausea and vomiting for people who are going through chemotherapy, research has not shown that RSO or other forms of cannabis oil can treat cancer. RSO has been claimed to have healing benefits for cancer, but as of 2022, no such properties are known.