RSO and FECO are similar cannabinoid-rich medicines used to treat cancer and reduce chronic pain. They are both gooey, sticky oils typically administered by syringe. The oil is usually eaten alongside fragrant or dense foods to mask its taste and consistency. Sometimes it’s even applied directly on the skin to help with inflammation or localized pain.

The difference in the two lies in the solvent used to extract the cannabinoids from the plant material. Rick Simpson Oil, or RSO, is made by soaking marijuana in 99% isopropyl alcohol, which is later boiled off at a high temperature. Some terpenes might get vaporized in this step but RSO usually retains a lot of the plant’s chlorophyll.

The process to make Full Extract Cannabis Oil, or FECO, uses grain alcohol (ethanol, Everclear) as a solvent. The process is done at a low temperature and retains a high level of the plant’s terpenes. Since food-grade grain alcohol is is safer for human consumption than iso alcohol, some people prefer FECO over RSO when ingesting or applying medical cannabis.