Halitosis is the medical term for bad breath. Causes range from poor oral hygiene to GI imbalances, and its occurrence has been tracked for thousands of years.

The ancient Greeks and Romans mention it in their texts, while Italy, Iraq, Thailand, and China, among many other countries, offer traditional folk cures such as tree resin, parsley, cloves, guava peels, and even egg shells! Sadly, bad breath causes social hesitation and psychological impairment in those it affects—it’s much more than a physical disease.

In this blog, we’ll explore bad breath causes and offer some practical cures, many of which you can safely try at home.

Bad Breath Causes

Halitosis is almost always caused by volatile sulfur compounds (VSCs), produced by overgrown or undesirable anaerobic bacteria feeding on amino acids, or broken down proteins. At least 80% of VSCs are made in the mouth. The gums, palate, tongue, tonsils, inside of the cheeks, and even the sinuses and ears can harbor these sulfur-producing bacteria (1).

Interestingly, there are multiple forms of halitosis, including pseudohalitosis and halitophobia. In pseudohalitosis, the affected person believes they have bad breath. Causes, however, cannot be identified. Halitophobia, sometimes called phantom bad breath, is an intense fear of halitosis. The fear is sometimes so severe that the person suffers from psychological symptoms without actually having bad breath.

While the large majority of bad breath causes occur in the mouth, about 13% are known as “extra-oral” and occur outside the mouth. These causes include H. pylori infection, chronic respiratory tract infections, gastric reflux disease,  hepatic and renal failure, dehydration, menstruation, overeating or poor digestion, and even garden variety stress.

These seemingly disparate underlying issues beg the question: is there a common thread that connects bad breath causes?

Almost every underlying reason for halitosis can be directly or indirectly linked back to an increase in sulfur compounds. And sulfur equals bad breath (2, 3).

However, two bad breath causes aren’t linked to sulfur: ketosis and excessive alcohol intake.

The state of dietary ketosis or diabetic ketoacidosis increases the number of ketone bodies in the bloodstream. Two ketone bodies, acetone and acetoacetate, can lead to fruity or metallic tasting and smelling breath (4).

In the case of heavy drinking, the culprit is a similar-sounding but different chemical: acetaldehyde. This ethanol metabolite can contribute to halitosis, especially when paired with the dry mouth that often accompanies alcohol consumption (5).

Bad Breath Cures

Because most halitosis comes from imbalances in the mouth, nose, ears, and throat, it’s most effective to investigate and address issues in these areas first.

Oral hygiene

Excellent oral hygiene is critical for avoiding bad breath.

  • thorough, twice-daily brushing, ideally with a Sonicare toothbrush (6)
  • flossing
  • use of an oral irrigator
  • regular dental checkups and cleanings
  • prompt attention to any gum inflammation, pain, or bleeding as these are symptoms of periodontal disease
  • smoking cessation

Periodontal disease, in particular, should be treated to prevent halitosis and preserve the health of the gums, teeth, and, surprisingly, the immune system and heart (7). Bad breath and diseased gums are strongly connected (8).

Green tea, vitamin C-rich foods such as bell peppers, citrus fruits, tomatoes, papaya, kiwi, strawberries, and canteloupe, and spices such as sumac and common black pepper may reduce the damage caused by periodontal disease (9).

You may also want to try toothpaste and mouthwash with neem, tea tree oil, myrrh, and/or rhatany (Krameria triandra) included as ingredients. Zinc may also be helpful as an ingredient in mouthwashes to neutralize VSCs and lessen the chances of bad breath. Zinc chloride is especially effective in neutralizing VSCs. And .5% zinc gluconate lozenges were shown to decrease VSCs and associated halitosis (10, 11). However, avoid mouthwashes or toothpastes that contain triclosan. Though it is antimicrobial, there are some concerns about its safety based on animal studies.

It may also help to use a tongue scraper, traditionally made of copper, and try oil pulling—both are Ayurvedic ways of keeping the mouth clean and healthy. Dry mouth can also contribute to bad breath, so do your best to stay hydrated.

Interestingly, coffee and tea may reduce the bacteria that release VSCs (12, 13). However, be careful with coffee if you experience acid reflux. Coffee (and garlic, as well) can trigger reflux and thus exacerbate halitosis instead of helping it. So, as always, it’s important to notice what is specifically helpful to you or not.

Spacing meals four to five hours apart, if possible, is a good idea. It gives your digestive system a break between meals and lets the mouth, tonsils, tongue, and stomach time to clean house via saliva, lymphatic movement, and the effects of the migratory motor complex in the small intestine.

Finally, pay special attention to your oral hygeine if you habitually wear a mask. The increased need for masking during the COVID-19 pandemic more than likely increased the incidences of dry mouth and halitosis. One study of over 400 healthcare workers found that dry mouth and halitosis increased by 28.5% with the more habitual use of personal protective equipment (14).

“It is less clear how many hours or days that non-healthcare individuals wear the same unsanitized face mask and whether exhaled, nasal, cutaneous, oral, oropharyngeal, and gastrointestinal organisms cultivated on the underside of the mask promote dysbiotic microbiomes and host illness” (15).

While the advantages of wearing a mask in certain environments outweigh the risks, we’re simply not sure of the side effects. So, make sure your mouth, and mask, stay as clean as possible.

Systemic health

Keeping the rest of your body balanced and healthy is important, too. Remember, approximately 13% of halitosis can be traced to sources outside the mouth.

Addressing systemic bacterial imbalances, especially in the oral cavity, sinuses, and GI tract, can be a bit tricky, but it’s a crucial step. Most bad breath stems from anaerobic bacteria, or bacteria that live without oxygen. While some anaerobes are associated with good health, such as Lactobacillus and Bifidobacterium, others are linked to poor health and symptoms like halitosis. Specifically, anaerobes such as Prevotella, Bacteroides, and Fusobacterium are bad breath causes.

H. pylori infection, most often associated with ulcers and gastric reflux, can also contribute to halitosis. Multiple strains of H. pylori produce VSCs such as hydrogen sulfide and methyl mercaptan (16). If you suspect you have a bacterial imbalance or H. pylori infection, work with a licensed clinician to get testing and treatment.

Pre and probiotics might be good ways to influence bacterially-influenced halitosis. While a 2022 systematic review and meta-analysis didn’t find a significant effect of probiotic supplementation on halitosis, the authors state that they believe there is a clinical effect (17). (Remember, statistical significance simply means that the results are likely not due to chance, not if the results are clinically useful.)

In recent years, certain studies have proposed [probiotics] to control plaque formation and prevent the breakdown of microbial homeostasis, acting on the maintenance and improvement of oral health (17).

And this study on the use of probiotics for halitosis is even published on the Colgate website!

Prebiotic foods, those that only feed beneficial bacterial strains, may also be useful. However, the main prebiotic foods are full of sulfur: onions, garlic, and leeks. While these foods are generally beneficial, they could lead to worsened breath. So, in the case of halitosis, stick with oats, Jerusalem artichokes, and what might be the halitosis superfood due to its high vitamin C levels and prebiotic fibers, kiwi.

Similarly, fermented foods may be problematic for those with bad breath. While fantastic for providing a diverse array of beneficial bacteria, they also contain VSCs. So, be aware of how these foods affect your unique biochemistry, especially cheese, wine, and beer (18).

Tips for Bad Breath Causes

Refer to this comprehensive list if you are working to address halitosis:

  • Optimize oral hygiene
  • Do your best to lessen alcohol and stop smoking
  • Proper hydration
  • Breathing through the nose (if you snore or breathe through your mouth during sleep, look into mouth taping)
  • Nigella sativa, spilanthes, and cleavers for gum health
  • Green tea
  • Eucalyptus extract (in chewing gum)
  • DGL, if there’s a digestive component (always consult your physician before beginning DGL due to its interaction with multiple medications and medical conditions)
  • Zinc carnosine, if there’s a digestive component
  • Pro and prebiotic foods
  • Vitamin c-rich foods
  • Zinc lozenges or mouth rinses
  • Addressing any underlying systemic issue that might contribute, such as gastric reflux
If you’re struggling with halitosis, make sure to reach out for help! You can learn more about my individualized client work here.

And if you’re a holistic health care practitioner looking to provide excellent client-centered support to your clients, check out my case study group.



  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4606616/
  2. https://pubmed.ncbi.nlm.nih.gov/20572919/
  3. https://www.researchgate.net/publication/312518148_Bad_breath_in_gastrointestinal_and_liver_diseases
  4. https://www.ncbi.nlm.nih.gov/books/NBK493179/
  5. https://www.sciencedirect.com/science/article/pii/S0020653920338016?ref=pdf_download&fr=RR-2&rr=740738282b8badb9
  6. https://pubmed.ncbi.nlm.nih.gov/28422462/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3100856/
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8509422/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4805154/
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5777415/
  11. https://www.tandfonline.com/doi/pdf/10.1080/08910600701521188
  12. https://pubmed.ncbi.nlm.nih.gov/21383472/
  13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8000802/
  14. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0266790
  15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8627006/
  16. https://pubmed.ncbi.nlm.nih.gov/16721224/
  17. https://www.frontiersin.org/articles/10.3389/fnut.2021.787908/full
  18. https://pubmed.ncbi.nlm.nih.gov/18064452/