What are essential oil monoterpenes' therapeutic uses?

Overview

Eucalyptus oil is a standard ingredient in cough drops and cough syrups, and an
oil added to humidifiers. A standardized combination of eucalyptus oil and two
other essential
oils has been studied for effectiveness in a variety of
respiratory conditions. This combination therapy contains cineole from eucalyptus,
d-limonene from citrus fruit, and alpha-pinene from pine. Because these oils are
all in a chemical family called monoterpenes, the treatment is called essential
oil monoterpenes. Diindolylmethane (DIM) also has complex interactions with
the hormone estrogen, which could lead to either positive or negative
effects on cancer risk.

Therapeutic Dosages

In studies, this essential oil combination was taken at a dose of 300 milligrams three to four times daily.

Therapeutic Uses

Most, though not all, studies indicate that oral use of essential oil
monoterpenes can help acute bronchitis, chronic bronchitis, and sinus
infections. For example, a double-blind, placebo-controlled trial of 676 people
with acute bronchitis found that two weeks of treatment with essential oil
monoterpenes was more effective than a placebo and just as effective as antibiotic
treatment for reducing symptoms and aiding recovery. In addition, a three-month,
double-blind, placebo-controlled trial of 246 people with chronic bronchitis found
that regular use of essential oil monoterpenes helped prevent the typical
worsening of chronic bronchitis that occurs during the winter. Additionally, in a
double-blind, placebo-controlled study of about three hundred people, use of
essential oil monoterpenes improved symptoms of acute sinusitis.
One study weakly indicates that essential oil monoterpenes may be helpful for
colds in children. Essential oil monoterpenes are thought to work by thinning
mucus.

Safety Issues

Other than minor gastrointestinal complaints, no side effects have been reported with this essential oil combination. However, be advised that essential oils can be toxic if taken in excess. Maximum safe doses in young children, women who are pregnant or nursing, and individuals with severe liver or kidney disease have not been established.

Bibliography

Behrbohm, H., O. Kaschke, and K. Sydow. “Effect of the Phytogenic Secretolytic Drug Gelomyrtol Forte on Mucociliary Clearance of the Maxillary Sinus.” Laryngorhinootologie 74 (1995): 733-737.

Matthys, H., et al. “Efficacy and Tolerability of Myrtol Standardized in Acute Bronchitis: A Multi-Centre, Randomised, Double-Blind, Placebo-Controlled Parallel Group Clinical Trial vs. Cefuroxime and Ambroxol.” Arzneimittel-Forschung 50 (2000): 700-711.

Meister, R., et al. “Efficacy and Tolerability of Myrtol Standardized in Long-Term Treatment of Chronic Bronchitis.” Arzneimittel-Forschung 49 (1999): 351-358.