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Aromatherapy and Essential Oils (PDQ®)

Patient Version
Last Modified: 10/19/2011

Questions and Answers About Aromatherapy

  1. What is aromatherapy?

    Aromatherapy is the use of essential oils from plants to support and balance the mind, body, and spirit. It is used by patients with cancer mainly as a form of supportive care that may improve quality of life and reduce stress and anxiety. Aromatherapy may be combined with other complementary treatments like massage therapy and acupuncture, as well as with standard treatments.

    Essential oils (also known as volatile oils) are the basic materials of aromatherapy. They are made from fragrant essences found in many plants. These essences are made in special plant cells, often under the surface of leaves, bark, or peel, using energy from the sun and elements from the air, soil, and water. If the plant material is crushed, the essence and its unique fragrance are released.

    When essences are extracted from plants in natural ways, they become essential oils. They may be distilled with steam and/or water, or mechanically pressed. Oils that are made with chemical processes are not considered true essential oils.

    There are many essential oils used in aromatherapy, including Roman chamomile, geranium, lavender, tea tree, lemon, cedarwood, and bergamot. Each type of essential oil has a different chemical structure that affects how it smells, how it is absorbed, and how it is used by the body. Even varieties of plants within the same species may have chemical structures different from each other because they are grown or harvested in different ways or locations.

    Essential oils are very concentrated. For example, it takes about 220 lbs of lavender flowers to make about 1 pound of essential oil. Essential oils are very volatile, evaporating quickly when they come in contact with air.

  2. What is the history of the discovery and use of aromatherapy as a complementary and alternative treatment for cancer?

    Fragrant plants have been used in healing practices for thousands of years across many cultures, including ancient China, India, and Egypt. Ways to extract essential oils from plants were first discovered during the Middle Ages.

    The history of modern aromatherapy began in the early 20th century, when French chemist Rene Gattefosse coined the term "aromatherapy" and studied the effects of essential oils on many kinds of diseases. In the 1980s and 1990s, aromatherapy was rediscovered in Western countries as interest in complementary and alternative medicine (CAM) began to grow.

  3. What is the theory behind the claim that aromatherapy is useful in treating cancer?

    Aromatherapy is rarely suggested as a treatment for cancer, but rather as a form of supportive care to manage symptoms of cancer or side effects of cancer treatment. There are different theories about how aromatherapy and essential oils work. A leading theory is that smell receptors in the nose may respond to the smells of essential oils by sending chemical messages along nerve pathways to the brain's limbic system, which affects moods and emotions. Imaging studies in humans help show the effects of smells on the limbic system and its emotional pathways.

  4. How is aromatherapy administered?

    Aromatherapy is used in various ways. Examples include:

    • Indirect inhalation (patient breathes in essential oils by using a room diffuser or placing drops nearby).

    • Direct inhalation (patient breathes in essential oils by using an individual inhaler with drops floated on top of hot water) to treat a sinus headache.

    • Aromatherapy massage (massaging essential oils, diluted in a carrier oil, into the skin).

    • Applying essential oils to the skin by combining them with bath salts, lotions, or dressings.

    Aromatherapy is rarely taken by mouth.

    There are some essential oils commonly chosen to treat specific conditions. However, the types of oils used and the ways they are combined may vary, depending on the experience and training of the aromatherapist. This lack of standard methods has led to conflicting research on the effects of aromatherapy.

  5. Have any preclinical (laboratory or animal) studies been conducted using aromatherapy?

    Many studies of essential oils have found that they have antibacterial effects when applied to the skin. Some essential oils have antiviral activity against the herpes simplex virus. Others have antifungal activity against certain vaginal and oropharyngeal fungus infections. In addition, studies in rats have shown that different essential oils can be calming or energizing. When rats were exposed to certain fragrances under stressful conditions, their behavior and immune responses were improved.

    One study showed that after essential oils were inhaled, markers of the fragrance compounds were found in the bloodstream, suggesting that aromatherapy affects the body directly like a drug, rather than indirectly through the central nervous system.

  6. Have any clinical trials (research studies with people) of aromatherapy been conducted?

    Clinical trials of aromatherapy have mainly studied its use in the treatment of stress, anxiety, and other health-related conditions in seriously ill patients. Several clinical trials of aromatherapy in patients with cancer have been published with mixed results.

    A few early studies have shown that aromatherapy may improve quality of life in patients with cancer. Some patients receiving aromatherapy have reported improvement in symptoms such as nausea or pain, and have lower blood pressure, pulse, and respiratory rates. Studies of aromatherapy massage have had mixed results, with some studies reporting improvement in mood, anxiety, pain, and constipation and other studies reporting no effect.

    A study of inhaled bergamot in children and adolescents receiving stem cell transplants reported an increase in anxiety and nausea and no effect on pain. Parents receiving the aromatherapy and parents receiving the placebo both showed less anxiety after their children’s transplants. In a study of adult patients receiving stem cell transplants, tasting or sniffing sliced oranges was more effective at reducing nausea, retching, and coughing than inhaling an orange essential oil.

    A small study of tea tree oil as a topical treatment to clear antibiotic -resistant MRSA bacteria from the skin of hospital patients found that it was as effective as the standard treatment. Antibacterial essential oils have been studied to lessen odor in necrotic ulcers.

    No studies in scientific or medical literature discuss aromatherapy as a treatment for cancer.

  7. Have any side effects or risks been reported from aromatherapy?

    Safety testing on essential oils shows very few bad side effects or risks when they are used as directed. Some essential oils have been approved as ingredients in food and are classified as GRAS (generally recognized as safe) by the U.S. Food and Drug Administration, within specific limits. Eating large amounts of essential oils is not recommended.

    Allergic reactions and skin irritation may occur in aromatherapists or in patients, especially when essential oils are in contact with the skin for long periods of time. Sun sensitivity may develop when citrus or other oils are applied to the skin before sun exposure.

    Lavender and tea tree oils have been found to have some hormone -like effects. They have effects similar to estrogen (female sex hormone) and also block or decrease the effect of androgens (male sex hormones). Applying lavender and tea tree oils to the skin over a long period of time has been linked in one study to breast enlargement in boys who have not yet reached puberty. It is recommended that patients with tumors that need estrogen to grow avoid using lavender and tea tree oils.

  8. Is aromatherapy approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

    Aromatherapy products do not need approval by the Food and Drug Administration because no specific claims are made for the treatment of cancer or other diseases.

    Aromatherapy is not regulated by state law, and there is no licensing required to practice aromatherapy in the United States. Professionals often combine aromatherapy training with another field in which they are licensed, for example, massage therapy, registered nursing, acupuncture, or naturopathy. Some aromatherapy courses for healthcare providers offer medical credit hours and include conducting research.

    The National Association for Holistic Aromatherapy (www.naha.org) and the Alliance of International Aromatherapists (www.alliance-aromatherapists.org) are two organizations that have national educational standards for aromatherapists. The National Association for Holistic Aromatherapy (NAHA) plans to have a standard aromatherapy certification in the United States. There are many schools that offer certificate programs approved by NAHA. A list of these schools can be found at http://www.naha.org/schools_level_one_two.htm. National exams 1 in aromatherapy are held twice a year.

    The Canadian Federation of Aromatherapists (www.cfacanada.com) certifies aromatherapists in Canada. See the International Federation of Aromatherapists Web site (www.ifaroma.org/) for a list of international aromatherapy programs.



Glossary Terms

acupuncture (AK-yoo-PUNK-cher)
The technique of inserting thin needles through the skin at specific points on the body to control pain and other symptoms. It is a type of complementary and alternative medicine.
allergic response (uh-LER-jik reh-SPONTS)
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.
androgen (AN-droh-jen)
A type of hormone that promotes the development and maintenance of male sex characteristics.
antibacterial (AN-tee-bak-TEER-ee-ul)
A substance that kills bacteria or stops them from growing and causing disease.
antibiotic (AN-tee-by-AH-tik)
A drug used to treat infections caused by bacteria and other microorganisms.
antifungal (AN-tee-FUN-gul)
A drug that treats infections caused by fungi.
antiviral (AN-tee-VY-rul)
A drug used to treat infections caused by viruses.
anxiety (ang-ZY-eh-tee)
Feelings of fear, dread, and uneasiness that may occur as a reaction to stress. A person with anxiety may sweat, feel restless and tense, and have a rapid heart beat. Extreme anxiety that happens often over time may be a sign of an anxiety disorder.
aromatherapy (uh-ROH-muh-THAYR-uh-pee)
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.
aromatherapy massage (uh-ROH-muh-THAYR-uh-pee muh-SAZH)
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.
bacteria (bak-TEER-ee-uh)
A large group of single-cell microorganisms. Some cause infections and disease in animals and humans. The singular of bacteria is bacterium.
bergamot (BER-guh-mot)
A type of orange tree grown in Italy. The essential oil from the peel of this orange is used in perfume, to get rid of insects, and to flavor tea. Bergamot oil is also used in aromatherapy for depression, anxiety, and poor digestion. The scientific name for the bergamot orange tree is Citrus bergamia.
blood pressure (blud PREH-sher)
The force of circulating blood on the walls of the arteries. Blood pressure is taken using two measurements: systolic (measured when the heart beats, when blood pressure is at its highest) and diastolic (measured between heart beats, when blood pressure is at its lowest). Blood pressure is written with the systolic blood pressure first, followed by the diastolic blood pressure (for example 120/80).
carrier oil (KAYR-ee-er oyl)
An oil with little or no scent that is used to dilute or “carry” essential oils (scented liquid taken from plants).
cedarwood (SEE-der-WOOD)
A type of evergreen tree with hard fragrant wood that is a member of the cypress family. The oil from the wood is used in soaps, shampoos, bath salts, perfumes, aromatherapy, and to keep insects away. The scientific name is Juniperus virginiana. Also called Eastern red cedar and red cedar.
cell (sel)
The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.
central nervous system (SEN-trul NER-vus SIS-tem)
The brain and spinal cord. Also called CNS.
clinical trial (KLIH-nih-kul TRY-ul)
A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.
complementary and alternative medicine (KOM-pleh-MEN-tuh-ree... all-TER-nuh-tiv MEH-dih-sin)
Forms of treatment that are used in addition to (complementary) or instead of (alternative) standard treatments. These practices generally are not considered standard medical approaches. Standard treatments go through a long and careful research process to prove they are safe and effective, but less is known about most types of CAM. CAM may include dietary supplements, megadose vitamins, herbal preparations, special teas, acupuncture, massage therapy, magnet therapy, spiritual healing, and meditation. Also called CAM.
complementary medicine (KOM-pleh-MEN-tuh-ree MEH-dih-sin)
Practices often used to enhance or complement standard treatments. They generally are not recognized by the medical community as standard or conventional medical approaches. Complementary medicine may include dietary supplements, megadose vitamins, herbal preparations, special teas, acupuncture, massage therapy, magnet therapy, spiritual healing, and meditation.
compound (KOM-pownd)
In science, a substance that is made up of more than one ingredient.
constipation (KON-stih-PAY-shun)
A condition in which stool becomes hard, dry, and difficult to pass, and bowel movements don’t happen very often. Other symptoms may include painful bowel movements, and feeling bloated, uncomfortable, and sluggish.
dilute (dy-LOOT)
To make something thinner, weaker, less concentrated, or less pure by adding something to it.
drug (drug)
Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.
essential oil (eh-SENT-shul oyl)
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.
estrogen (ES-truh-jin)
A type of hormone made by the body that helps develop and maintain female sex characteristics and the growth of long bones. Estrogens can also be made in the laboratory. They may be used as a type of birth control and to treat symptoms of menopause, menstrual disorders, osteoporosis, and other conditions.
Food and Drug Administration (... ad-MIH-nih-STRAY-shun)
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.
fragrance (FRAY-grunts)
A pleasant, sweet odor.
fungus (FUN-gus)
A plant-like organism that does not make chlorophyll. Mushrooms, yeasts, and molds are examples. The plural is fungi.
geranium (jeh-RAY-nee-um)
A type of plant that is native to southern Africa and has white, pink, purple, or red flowers and 3- to 5-lobed leaves. An essential oil that smells like roses is taken from the leaves and used in perfume, in mosquito repellants, and in aromatherapy to treat skin problems and to reduce stress. The scientific name is Pelargonium graveolens. Also called pelargonium.
healthcare provider (HELTH-kayr proh-VY-der)
A licensed person or organization that provides healthcare services.
herpes simplex virus (HER-peez SIM-plex VY-rus)
A type of virus that causes herpes infections and has DNA as its genetic material. There are two types of herpes simplex viruses. Infections with type 1 viruses cause cold sores on the lips or nostrils. Infections with type 2 viruses cause sores on the genitals (external and internal sex organs and glands). Also called HHV, HSV, and human herpesvirus.
hormone (HOR-mone)
One of many chemicals made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.
imaging (IH-muh-jing)
In medicine, a process that makes pictures of areas inside the body. Imaging uses methods such as x-rays (high-energy radiation), ultrasound (high-energy sound waves), and radio waves.
immune response (ih-MYOON reh-SPONTS)
The activity of the immune system against foreign substances (antigens).
infection (in-FEK-shun)
Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.
inhalation (IN-huh-LAY-shun)
In medicine, refers to the act of taking a substance into the body by breathing.
inhaler (in-HAY-ler)
A device for giving medicines in the form of a spray that is inhaled (breathed in) through the nose or mouth. Inhalers are used to treat medical problems such as bronchitis, angina, emphysema, and asthma. They are also used to help relieve symptoms that occur when a person is trying to quit smoking.
lavender (LA-ven-der)
A plant with aromatic leaves and flowers that is a member of the mint family. Oil from the flowers has been used in some cultures to treat certain medical problems, to keep insects away, and to wash in. It is also used in aromatherapy. Perillyl alcohol, a substance found in lavender, is being studied in cancer prevention and treatment. The scientific name is Lavandula angustifolia. Also called English lavender and true lavender.
lemon (LEH-mun)
A small, yellow citrus fruit that is a source of citric acid and ascorbic acid (vitamin C). The juice is used to flavor food and drink and to prevent scurvy. Lemon oil (scented liquid taken from the peel) is used in aromatherapy. The scientific name of the lemon tree is Citrus limon.
limbic system (LIM-bik SIS-tem)
A network of structures in the brain involved in memory and emotions.
massage therapy (muh-SAZH THAYR-uh-pee)
A treatment in which the soft tissues of the body are kneaded, rubbed, tapped, and stroked. Massage therapy may help people relax, relieve stress and pain, lower blood pressure, and improve circulation. It is being studied in the treatment of cancer symptoms such as lack of energy, pain, swelling, and depression.
naturopathy (NAY-cher-AH-puh-thee)
A system of disease prevention and treatment that avoids drugs and surgery. Naturopathy is based on the use of natural agents such as air, water, light, heat, and massage to help the body heal itself. It also uses herbal products, nutrition, acupuncture, and aromatherapy as forms of treatment.
nausea (NAW-zee-uh)
A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.
necrosis (neh-KROH-sis)
Refers to the death of living tissues.
nerve (nerv)
A bundle of fibers that receives and sends messages between the body and the brain. The messages are sent by chemical and electrical changes in the cells that make up the nerves.
oropharynx (OR-oh-FAYR-inx)
The part of the throat at the back of the mouth behind the oral cavity. It includes the back third of the tongue, the soft palate, the side and back walls of the throat, and the tonsils.
placebo (pluh-SEE-boh)
An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.
quality of life (KWAH-lih-tee ... life)
The overall enjoyment of life. Many clinical trials assess the effects of cancer and its treatment on the quality of life. These studies measure aspects of an individual’s sense of well-being and ability to carry out various activities.
retch (RECH)
The action of the stomach and esophagus to try to vomit (eject some or all of the contents of the stomach). Retching that does not cause vomiting is called dry heaves.
Roman chamomile (ROH-mun KA-muh-mile)
A type of chamomile plant with daisy-like white flowers that is found in Europe, North America, and Argentina. The dried flowers are used in teas to calm and relax, to improve sleep, and to help with stomach problems. Its essential oil (scented liquid taken from plants) is used in perfumes, shampoos, face creams, lotions, and aromatherapy. The scientific names are Chamaemelum nobile and Anthemis nobilis. Also called English chamomile.
sensitivity (SENT-sih-TIH-vih-tee)
When referring to a medical test, sensitivity refers to the percentage of people who test positive for a specific disease among a group of people who have the disease. No test has 100% sensitivity because some people who have the disease will test negative for it (false negatives).
side effect (side eh-FEKT)
A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.
sinus (SY-nus)
A cavity, space, or channel in the body. Examples include hollow spaces in the bones at the front of the skull, and channels for blood and lymph. Sinuses may also be found in the heart, brain, and other organs.
standard therapy (... THAYR-uh-pee)
Treatment that experts agree is appropriate, accepted, and widely used. Also called best practice, standard medical care, and standard of care.
stem cell transplant (stem sel tranz-plant)
A method of replacing immature blood-forming cells in the bone marrow that have been destroyed by drugs, radiation, or disease. Stem cells are injected into the patient and make healthy blood cells. A stem cell transplant may be autologous (using a patient’s own stem cells that were saved before treatment), allogeneic (using stem cells donated by someone who is not an identical twin), or syngeneic (using stem cells donated by an identical twin).
supportive care (suh-POR-tiv kayr)
Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal of supportive care is to prevent or treat as early as possible the symptoms of a disease, side effects caused by treatment of a disease, and psychological, social, and spiritual problems related to a disease or its treatment. Also called comfort care, palliative care, and symptom management.
symptom (SIMP-tum)
An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.
tea tree (tee tree)
A tree that is a member of the myrtle family. Oil from the tea tree is used in shampoos and skin care products and to treat skin infections. It has been used in some cultures to treat other skin conditions, including acne, burns, and insect bites. The scientific name is Melaleuca alternifolia.
tumor (TOO-mer)
An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.
ulcer (UL-ser)
A break on the skin, in the lining of an organ, or on the surface of a tissue. An ulcer forms when the surface cells become inflamed, die, and are shed. Ulcers may be linked to cancer and other diseases.
vaginal (VA-jih-nul)
Having to do with the vagina (the birth canal).

Table of Links

1http://www.aromatherapycouncil.org