One should never use synthetic oils and oils extracted by chemical solvents. Many synthetic oils on the market today replicate the fragrances of natural oils, and many people unknowingly use them, hopig to derive their benefits. The synthetic chemicals that create these products do not contain the beneficial properties of pure plant oils. In addition, may synthetic compounds can be very irritating to the body and nervous system. Oils extracted with solvents contain toxic residue harmful to the body. It is imortant to select unrefined carrier oils, and essential oils extracted by steam distillation or which have been pressed mechanically or by an expeller.