Unlike many other cannabis oils, Rick Simpson Oil is high in tetrahydrocannabinol (THC), which is the main psychoactive chemical in marijuana. THC is the chemical in marijuana that provides the "high." 
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Simpson is a Canadian engineer and cannabis activist. After a bad fall, he found that marijuana helped lessen his dizziness and other symptoms. Later, when he developed basal cell skin cancers on his arm, Simpson used cannabis oil as a treatment. As the reports go, his skin cancers went away. 
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RSO is not a branded product. That means there's no one "Rick Simpson Oil" for sale. On his website, Simpson explains how to make his namesake oil. But he does not sell a version of the oil for profit.