Research on the effectiveness of aromatherapy — the therapeutic use of essential oils extracted from plants — is limited.

However, some studies have shown that aromatherapy might have health benefits, including:

• Relief from anxiety and depression
• Improved quality of life, particularly for people with chronic health conditions
• Improved sleep

Smaller studies suggest that aromatherapy with lavender oil may help:

• Reduce pain for people with osteoarthritis of the knee
• Improve quality of life for people with dementia
• Reduce pain for people with kidney stones

Essential oils used in aromatherapy are typically extracted from various parts of plants and then distilled. The highly concentrated oils may be inhaled directly or indirectly or applied to the skin through massage, lotions or bath salts. Some essential oil manufacturers have oils that can be taken internally, but research on the safety and efficacy of this method is extremely limited.

Aromatherapy is thought to work by stimulating smell receptors in the nose, which then send messages through the nervous system to the limbic system — the part of the brain that controls emotions.

Many essential oils have been shown to be safe when used as directed. However, essential oils used in aromatherapy aren't regulated by the Food and Drug Administration.

When oils are applied to the skin, side effects may include allergic reactions, skin irritation and sun sensitivity. In addition, further research is needed to determine how essential oils might affect children and how the oils might affect women who are pregnant or breast-feeding, as well as how the oils might interact with medications and other treatments.

If you're considering aromatherapy, consult your doctor and a trained aromatherapist about the possible risks and benefits.