Essential oils are highly concentrated, and are rigorously tested for general safety. But those who may be allergic to certain components in such oil will have a severe reaction if exposed to this concentrated amount of allergen. For safety’s sake, always perform an allergy test when you acquire a new essential oil or blend of oils.

To do a home allergy test, first choose a trusted carrier oil that is known not to cause an allergic reaction. Carrier oils, also known as base oils, are the oils used to dilute essential oils for certain uses. They usually have very little aroma themselves, so as not to interfere with the qualities of the essential oil. Good carrier oils include jojoba oil, sweet almond oil, olive oil, and many other options. Once you have a carrier oil you trust, make a solution using one drop of essential oil to ten drops of carrier oil. Apply this mixture to the inside of the wrist or elbow, and wait 48 hours. If there is no reaction, the essential oil is probably safe for you to use as a fragrance or therapeutic oil.