The cannabis oil that is typically available in dispensaries is THC-dominant with little cannabidiol. To extract CBD-rich cannabis oil, one must start with CBD-rich plant material. There many ways to extract oil from the cannabis plant, each has its pros and cons. Some methods are safer and more effective than others. Cannabis oils made with neurotoxic solvents like butane and hexane may leave unsafe residues that interfere with immune function and impede healing. Supercritical CO2 extraction is non-toxic and produces high quality oil, but requires significant expertise and access to expensive equipment. Home-brewers can also use safer solvents, such as ethanol, or prevent exposure to organic solvents entirely by using olive oil to extract cannabis oil, according to Dr. Arno Hazekamp director of phytochemical research at Bedrocan BV, which supplies cannabis, including a CBD-rich strain, for the Dutch Health Ministry’s medical marijuana program.