Safety testing on essential oils has shown minimal adverse effects. Several oils have been approved for use as food additives and are classified as generally recognized as safe (GRAS) by the U.S. Food and Drug Administration; however, ingestion of large amounts of essential oils is not recommended. In addition, a few cases of contact dermatitis have been reported, mostly in aromatherapists who have had prolonged skin contact with oils in the context of aromatherapy massage.[1] Some essential oils (e.g., camphor oil) can cause local irritation; therefore, care should be taken when applying them. Phototoxicity has occurred when essential oils (particularly citrus oils) are applied directly to the skin before sun exposure. One case report also showed airborne contact dermatitis in the context of inhaled aromatherapy without massage.[2] Most often, aromatherapy uses undefined mixtures of essential oils without specifying the plant sources. Allergic reactions are sometimes reported, especially following topical administration. As essential oils age, they are often oxidized so the chemical composition changes. Individual psychological associations with odors may result in adverse effects. Repeated exposure to lavender and tea tree oils by topical administration has been associated with reversible prepubertal gynecomastia. Lavender and tea tree oils have estrogenic and antiandrogenic activities, and there is a theoretical concern for women at high risk for hormonally sensitive breast cancer when using lavender and tea tree oils.[3]

References

1. Bilsland D, Strong A: Allergic contact dermatitis from the essential oil of French marigold (Tagetes patula) in an aromatherapist. Contact Dermatitis 23 (1): 55-6, 1990.  [PUBMED Abstract]
   
   
2. Schaller M, Korting HC: Allergic airborne contact dermatitis from essential oils used in aromatherapy. Clin Exp Dermatol 20 (2): 143-5, 1995.  [PUBMED Abstract]
   
   
3. Henley DV, Lipson N, Korach KS, et al.: Prepubertal gynecomastia linked to lavender and tea tree oils. N Engl J Med 356 (5): 479-85, 2007.  [PUBMED Abstract]
   
   

Glossary Terms

An unwanted side effect of treatment.

A hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in most people. An allergic response may cause harmful symptoms such as itching or inflammation or tissue injury.

A type of complementary and alternative medicine that uses plant oils that give off strong pleasant aromas (smells) to promote relaxation, a sense of well-being, and healing.

A type of complementary and alternative medicine that uses rubbing and kneading of the skin with plant oils that give off strong, pleasant aromas (smells) to promote relaxation, a sense of well-being, and healing.

A substance that comes from the wood and bark of the camphor tree or is made in the laboratory. It has a very unique smell and taste and is used in commercial products (for example, mothballs). Camphor is used in topical anti-infective and anti-pruritic (anti-itching) agents.

A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin).

Inflammation of the skin.

The scented liquid taken from certain plants using steam or pressure. Essential oils contain the natural chemicals that give the plant its “essence” (specific odor and flavor). Essential oils are used in perfumes, food flavorings, medicine, and aromatherapy.

FDA. An agency in the U.S. federal government whose mission is to protect public health by making sure that food, cosmetics, and nutritional supplements are safe to use and truthfully labeled. The Food and Drug Administration also makes sure that drugs, medical devices, and equipment are safe and effective, and that blood for transfusions and transplant tissue are safe. Also called FDA.

Taking into the body by mouth.

In medicine, refers to the act of taking a substance into the body by breathing.

A smell.

A condition in which the skin or eyes become very sensitive to sunlight or other forms of light. It can be caused by taking certain drugs, or rubbing certain essential oils (scented liquid taken from plants) or other topical agents into the skin. Phototoxicity causes sunburn, blisters, and other skin problems.