Eucalyptus oil is a standard ingredient in cough drops and cough syrups, as well as oils added to humidifiers. A standardized combination of eucalyptus oil plus 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.”
DIM also has complex interactions with the hormone estrogen, which could lead to either positive or negative effects on cancer risk.
Most, though not all, studies indicate that oral use of essential oil monoterpenes can help acute bronchitis, chronic bronchitis, and sinus infections.2-7
For example, a double-blind, placebo-controlled trial of 676 people with acute bronchitis found that 2 weeks treatment with essential oil monoterpenes was more effective than placebo and equally effective as antibiotic treatment for reducing symptoms and aiding recovery.5 Also, a 3-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.4
One study weakly indicates that essential oil monoterpenes may be helpful for colds in children.1
Essential oil monoterpenes are thought to work by thinning mucus.
In studies, this essential oil combination was taken at a dose of 300 mg three to four times daily.
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.
1. Sengespeik HC, Zimmermann T, Peiske C, et al. Myrtol standardized in the treatment of acute and chronic respiratory infections in children. A multicenter post-marketing surveillance study. Arzneimittelforschung. 1998;48:990–994.
2. Federspil P, Wulkow R, Zimmermann T. Effects of standardized Myrtol in therapy of acute sinusitis—results of a double-blind, randomized multicenter study compared with placebo. Laryngorhinootologie. 1997;76:23–27.
3. Behrbohm H, Kaschke O, Sydow K. Effect of the phytogenic secretolytic drug Gelomyrtol forte on mucociliary clearance of the maxillary sinus. Laryngorhinootologie. 1995;74:733–737.
4. Meister R, Wittig T, Beuscher N, et al. Efficacy and tolerability of Myrtol standardized in long-term treatment of chronic bronchitis. A double-blind, placebo-controlled study. Study Group Investigators. Arzneimittelforschung. 1999;49:351–358.
5. Matthys H, de Mey C, Carls C, 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. Arzneimittelforschung. 2000;50:700–711.
6. Ulmer WT, Schott D. Chronic obstructive bronchitis. Effect of Gelomyrtol forte in a placebo-controlled double-blind study. Fortschr Med. 1991;109:547–550.
7. Dorow P, Weiss T, Felix R, et al. Effect of a secretolytic and a combination of pinene, limonene and cineole on mucociliary clearance in patients with chronic obstructive pulmonary. Arzneimittelforschung. 1987;37:1378–1381.
Last reviewed December 2015 by EBSCO CAM Review Board Last Updated: 12/15/2015