dōTERRA CPTG Certified Pure Therapeutic Grade essential oils represent the safest and most beneficial oils available in the world today. For an oil to be CPTG Certified Pure Therapeutic Grade the oil must be: Pure and natural, with aromatic compounds carefully extracted from plants Free from fillers or artificial ingredients; no dilution of active qualities Free of contaminants, pesticides, or chemical residues Rigorously tested for standards of chemical composition Cross tested using mass spectrometry and gas chromatography to ensure exact purity and composition potency Sourced by a global network of leading essential oil chemists and growers to ensure correct species, growth in ideal environments, and that raw plant materials were carefully harvested at the right time.