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Eucalyptus is a large tree that is known for its pleasant smell. It has been used to improve mouth odor. Its leaves and flowers can be taken as a pill, powder, extract, or made into a tea. Eucalyptus is also used as a cream, salve, and essential oil.


There are no advised doses for eucalyptus.

What Research Shows

Not Enough Data to Assess

  • Gingivitis A1
  • Halitosis (bad breath) B1, B2

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe for most adults to use eucalyptus on the skin. It is also likely safe to take orally for a short time. Undiluted eucalyptus oil should not be applied to the skin or taken orally. Eucalyptus oil should not be used by children or during pregnancy and breastfeeding. Not enough studies have been done to say whether it is safe to use eucalyptus for a long period.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse, such as:

  • People with diabetes should talk to their doctors before taking eucalyptus. It may interact with their medicines.
  • People taking barbiturates should talk to their doctors before taking eucalyptus. It may make the medicine less effective.


A. Gingivitis

A1. Keukenmeester RS, Slot DE, et al. The effect of medicated, sugar-free chewing gum on plaque and clinical parameters of gingival inflammation: a systematic review. Int J Dent Hyg. 2014 Feb;12(1):2-16.

B. Halitosis

B1. Tanaka M, Toe M, et al. Effect of eucalyptus-extract chewing gum on oral malodor: a double-masked, randomized trial. J Periodontol. 2010;81(11):1564-1571.

B2. Muniz FW, Friedrich SA, et al. The impact of chewing gum on halitosis parameters: a systematic review. J Breath Res. 2017 Feb 17;11(1):014001.

Last reviewed July 2019 by EBSCO NAT Review Board Eric Hurwitz, DC  Last Updated: 5/6/2020