Rectification is a form of fractioning, coarser than fractional distillation, that separates the odor molecules of an essential oil that have very different boiling temperatures. The odorant compounds of the essential oil pass one after the other into the distillation column and are collected separately, after condensation. Molecules with no olfactory value are then removed from the essential oil, while the desired molecules are concentrated. Our Chinese eucalyptus globulus 80% essential oil (high cineole content) and Chinese spearmint 80% (high carvone content) are rectified essential oils.