Essential oils have a shelf life. Generally speaking, the essential oil can be stored for about 3 years in a sealed state. If the essential oil has been opened, it should be used up within 3 months, otherwise the efficacy may decline. The specific shelf life of essential oil shall be subject to the instructions of the product. Essential oil refers to the general name of volatile aromatic substances extracted from spice plants or fragrant secreting animals. Essential oils are divided into diluted (compound essential oils) and undiluted (unilateral essential oils).
Essential oil is a volatile aromatic substance extracted from flowers, leaves, roots, seeds, fruits, bark, resin, wood core and other parts of plants by steam distillation, cold pressing, fat absorption or solvent extraction.
The history of plant essential oils can be traced back to ancient China, Egypt, Arabia and Greece. It was said that Shennong tasted all kinds of herbs during the period of 'Three Emperors and five emperors'. （JingYouYouBaoZhiJiMa）