Can you believe that an oil that is sold in the US with a label that says 100% pure essential oil, really only has to be 10% pure essential oil. The other 90% in that bottle is synthetics, alcohol and/or fillers. This is not oil that is therapeutic, but it is what you found in many stores that sell essential oils. Adulterated oils most likely will not produce therapeutic results and could possibly be toxic. Check the label, if it says "for external use only" or "for aromatic use only", that indicates that it is NOT therapeutic grade. If the label has Supplement Facts, then you have found a therapeutic grade oil. My thought is if I can eat basil or peppermint why shouldn't I be able to eat the essential oils from those same plants?
Young Living Essential Oils is a company I trust. They are the only essential oil company that sends their oils to France to be tested by AFNOR (Association French Normalization Organization Regulation). In Europe, a set of standard has been established that outlines the chemical profile and principal consituents that a quality essentia oil should have - this is tested by AFNOR.