Aromatherapy Explained Simply

1. What It Is About

Aromatherapy is the use of essential oils. They are most commonly inhaled: the oil is vaporised or placed on a cloth, and the scent is drawn into the nose. Some studies also apply the oils to the skin, often as a massage. The application is frequently combined with something else, such as music. Oils investigated include lavender, Damask rose, peppermint and bergamot, either singly or as a blend.

It is important that aromatherapy is not a single substance. In every study something different comes together: the scent, the touch during a massage, a calm environment and the attention from the person accompanying the application. Added to this is the expectation of the participants.

What is measured is almost always what the participants report themselves: how anxious they feel, what their mood is like, how well they have slept, how severe the pain is. Such statements also depend on how much attention someone receives. Another point: a scent can hardly be concealed. Anyone who receives a scented oil usually notices it, and a comparison substance without odour stands out.

2. What Studies Show

The findings on anxiety are the best supported. A summary of six studies on anxiety before a dental visit 4 found lower anxiety scores in the treated groups than in the comparison groups; the certainty of this statement is rated as high. For this field of application the association is therefore considered well established.

In cancer patients one overview 1 summarises eleven studies. Ten of them examined anxiety in 1724 patients, five examined depressed mood in 1039 patients. In both cases the scores were lower in the groups with aromatherapy. The quality of the individual studies is rated as low, however, so these are indications but not yet confirmed. A further overview 2 evaluated ten studies on sleep quality in 933 cancer patients. Sleep improved, especially in women with breast cancer; a single oil performed better than a blend.

In 200 patients before an MRI examination 6 lavender was inhaled, music was listened to, or both. The strongest calming effect occurred when both were combined: anxiety decreased most markedly in this group, more markedly than with lavender or music alone.

After surgery for a fracture of the leg or foot 7 lemon oil was inhaled in 90 patients. The groups differed markedly in pain as well as in nausea and vomiting. Whether the comparison group received an oil without active ingredient remains open; therefore it is not possible to separate how much is due to the scent and how much to expectation. A further summary 9 of 44 studies reports that pain decreased in the majority of studies, most markedly in labour pain and after operations.

3. What Remains Unclear

The greatest open question is the comparison group. Control groups usually receive water, paraffin oil or almond oil or only usual care. What is then measured cannot be clearly attributed to the oil.

The applications themselves are also described differently: oil, duration and environment vary from study to study. One overview 5 of 76 studies with 6539 patients cites the imprecise specification of plant variety and quantity of oil as a limitation.

For cancer pain one evaluation 8 showed that pain decreased. Whether inhaled oils change anything in the intestine is open; no study with corresponding measured values exists for this. Likewise, testing in humans is still outstanding as to whether inflammatory markers or markers of oxidative stress in the blood change.

4. What This Means in Everyday Life

Anyone reading the findings should distinguish two things: what participants report about their well-being and what was measured without anyone having to say anything about it. The reported improvements in anxiety, depressed mood and sleep are well to moderately supported; heart rate, blood pressure and oxygen saturation changed in several studies as well, but not uniformly.

Aromatherapy was almost always tested in addition to usual care, not as the sole measure. Whether it works on its own has therefore not yet been clarified. Nor has it been clarified how the interaction with music is to be explained; the studies with MRI patients and with children at the dentist suggest that the combination changes more.

What would be needed next are blinded studies that use a comparison substance with the same odour, specify the variety and quantity of the oil precisely and also record tolerability.

All details with study numbers and sources: detailed page on aromatherapy. For children: Aromatherapy for children.