Looking for a solution to your bad breath? Perhaps you’ve heard that essential oils like tea tree oil can help bad breath. Here, we cover the evidence of essential oils like tea tree oil and how they can fix bad breath.

What causes bad breath?

Bad breath, often known as halitosis, is caused mostly by particular bacterial species in your mouth. These bacteria are part of the oral microbiome, a community of organisms that reside in your mouth that includes bacteria, fungi, viruses, and archaea. According to research, 90+% of all occurrences of halitosis are intra-oral, meaning they originate within the mouth. Only about 10% of cases are extra-oral or are classified as pseudo-halitosis.

How bacteria in your mouth cause bad breath

Many of the bacteria in your oral microbiome are anaerobic, which means they cannot thrive in the presence of oxygen and instead generate energy from other substances such as sulfur. These bacteria produce unpleasant byproducts such as hydrogen sulfide and propionic acid during anaerobic respiration, the process of creating energy without the need of oxygen. Unfortunately, even with routine hygiene like brushing, flossing, and mouthwash, these bacteria may persist in the mouth because none of these entirely remove all of the bacteria in the mouth, and these bacteria can rapidly proliferate.

Other non-smelly bacterial species in the oral microbiome, known as commensal, or beneficial species, may actually prevent those smelly bacteria from returning. We'll go over these commensal bacteria in greater detail later. Most humans have a healthy balance of these beneficial species that keep the harmful ones at bay. However, patients with persistent bad breath frequently lack these commensal species, allowing the detrimental odorous ones to thrive. Oral dybiosis is a term used to describe this microbial imbalance. You can real more about oral microbiome dysbiosis in an article here.

What is essential oil?

We’ve done a deep dive into the benefits of essential oils and how they work! If you want to read that article, we’ve linked it here. But if you just want a quick summary:

Essential oils are natural products that are produced by plants. People have used essential oils from a variety of plants for thousands of years, and recent research has demonstrated how they work. Many of these essential oils are antibacterial or antifungal, and are able to either inhibit the growth of bacteria or directly kill them.

What is tea tree oil?

Tea tree oil is oil extract from a tea tree! It’s as simple as that. Tea tree oil is also known as melaleuca oil because it comes from a Melaleuca plant.

How should you use tea tree oil?

Tea tree oil in mouthrinses is safe to use, but should never be ingested. Tea tree oil can cause a number of side effects if ingested, such as dizziness, hallucinations, vomiting, and diarrhea. Mouthrinses infused with tea tree oil should only be swished in the mouth and spat out, never swallowed.

Does tea tree oil help bad breath?

In summary, yes, tea tree oil has been shown to reduce bad breath, and inhibit the growth of bacteria that cause bad breath.

One clinical trial showed that tea tree oil (Melaleuca alternifolia) administered as a gel suppressed a number of bacterial colonies and dental biofilm.

Another laboratory study showed that tea tree oil also reduced the production of hydrogen sulfide, a key chemical that causes bad breath. Additionally, tea tree oil can kill Porphyromonas gingivalis and Porphyromonas endodontalis, two bacteria in the oral microbiome that cause bad breath.

It also possesses antifungal properties that may help it reduce the abundance of Candida, the yeast that causes thrush.