Rick Simpson Oil (RSO) is a concentrated cannabis extract known for its high potency and wide range of potential medicinal applications. Named after the Canadian cannabis activist Rick Simpson, who popularized its use, RSO is often regarded as a holistic alternative for managing various medical conditions.Rick Simpson Oil (RSO) is a concentrated cannabis extract known for its high potency and wide range of potential medicinal applications. Named after the Canadian cannabis activist Rick Simpson, who popularized its use, RSO is often regarded as a holistic alternative for managing various medical conditions.