Essential oils enter the body in three ways. They can be:

1. Applied to the skin
2. Inhaled
3. Ingested

Essential oils can be applied topically to the skin. Common examples include applying a blend that contains black pepper (Piper nigrum) or ginger (Zinziber officinalis) essential oil to reduce arthritis pain and improve flexibility, or applying German Chamomile (Matricaria recutita) essential oil to treat eczema, Lavender for Highblood pressure.

Our skin is somewhat permeable. The active chemicals in essential oils are absorbed just like the ingredients in common pharmaceuticals such as hormone replacement therapy cream and nicotine patches.

Another way that essential oils enter the body is inhalation through the nose or mouth. Common examples include inhaling eucalyptus (Eucalyptus globules, E. radiate, or E. smithii) essential oil when you have a cough or inhaling peppermint (Mentha piperita) essential oil to reduce fatigue or nausea. (Note: Often, essential oils are put into a diffuser for inhalation. Molecules inhaled through the nose or mouth are also carried to the lungs and interact with the respiratory system. Thus, inhaled essential oils can affect the body through several systems and pathways.

The ingestion of essential oils is not common practice in the US. In France, it is more common, but only when specially trained physicians and pharmacists prescribe and dispense them. There are several reasons for caution, including the following:

• Some essential oils can be toxic to the liver or kidneys when ingested.
• Chemical breakdown of essential oils during gastric processing can change the effects.
• There could be potential drug interactions.