Bad breath, medically known as halitosis, affects millions of people worldwide. Although it's a very common problem, it's largely a taboo subject in society. Hardly anyone likes to talk about it openly, even though the impact on social life, self-confidence, and even professional situations can be significant. But how exactly does bad breath arise? And what can be done about it? In this comprehensive article, we examine the phenomenon from various perspectives: medical, biological, and practical. The goal is not only to identify the causes but also to demonstrate lasting, effective solutions.
What is bad breath actually?
Bad breath describes an unpleasant odor that is noticeable when exhaling from the mouth. A distinction must be made between temporary bad breath (e.g., after eating certain foods like garlic or onions) and chronic bad breath, which occurs regularly and independently of external influences. Approximately 85 to 90 percent of cases of bad breath originate directly in the oral cavity.
The role of bacteria in the mouth
The oral cavity is a complex biological environment with billions of microorganisms. Many of these bacteria are harmless or even beneficial. However, some produce so-called volatile sulfur compounds (VSCs) when decomposing food debris or dead cells, which are responsible for the unpleasant odor. These include hydrogen sulfide, methyl mercaptan, and dimethyl sulfide.
These substances are primarily produced when anaerobic bacteria—those that do not require oxygen—multiply. These bacteria find ideal conditions in poorly cleaned interdental spaces, in gum pockets, or on the back of the tongue. The rough surface of the back of the tongue, in particular, provides an ideal breeding ground for odor-producing microorganisms.
The most common causes of bad breath in detail
The causes of bad breath are varied, but the vast majority are related to the oral cavity itself. The main factors include:
Poor oral hygiene
Inadequate or irregular brushing and a lack of interdental cleaning lead to plaque, in which bacteria multiply rapidly. Food debris in the spaces between teeth or on the tongue also contribute to the development of odor.
Tongue coating
The back of the tongue is often neglected during daily brushing. Dead cells, food debris, and bacteria accumulate there—an ideal breeding ground for odorous metabolic processes.
Periodontitis and gingivitis
Inflammation of the gums or periodontal ligament not only causes pain and tooth loosening, but also promotes the development of anaerobic bacteria that release sulfur compounds.
Dry mouth (xerostomia)
Saliva plays a central role in cleaning the oral cavity. It rinses away food debris, neutralizes acids, and has an antimicrobial effect. If saliva production is reduced—for example, due to certain medications, insufficient fluid intake, or snoring at night—odor-causing substances can accumulate more easily.
Nutrition
Spicy foods, alcohol, coffee, and onion plants directly influence breath odor. These causes are usually temporary and can be easily controlled through hygienic measures.
Smoke
Tobacco consumption changes the oral flora, reduces saliva production and dries out the mucous membranes – a combination that increases bad breath and at the same time makes it more difficult for the mouth to clean itself.
Systemic causes
In approximately 10–15% of cases, the cause of bad breath is not in the mouth, but rather internal to the body. Possible triggers include:
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Diseases of the gastrointestinal tract
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Inflammation of the nasopharynx
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Diabetes mellitus ("acetone smell")
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Liver or kidney failure These forms of halitosis must be medically diagnosed and treated specifically.
Table: Causes of bad breath at a glance
| Caused | Description | Share of cases |
|---|---|---|
| Poor oral hygiene | Plaque, food residue, bacterial deposits | approx. 40% |
| Tongue coating | Dead cells and bacteria on the back of the tongue | approx. 30% |
| Gingivitis | Gingivitis, periodontitis | approx. 10–15% |
| Dry mouth | Lack of saliva due to medication or habits | approx. 10% |
| Systemic diseases | Stomach, liver, kidneys, respiratory tract | approx. 10–15% |
How is bad breath diagnosed?
The diagnosis of bad breath is usually performed by a dentist or halitosis specialist. A simple method is the so-called "quick wrist test" or the "breathing test." More objective methods use special gas chromatographs or sulfur monitors to measure the concentration of VSCs. A microbiological analysis of the tongue coating can also provide information about the bacterial causes.
What helps sustainably against bad breath?
The most effective measure against bad breath is consistent and comprehensive oral hygiene. This should include not only brushing your teeth, but also cleaning your tongue and the spaces between your teeth. Tongue cleaners and interdental brushes have proven particularly effective. Additionally, an antiseptic mouthwash can help reduce the number of odor-causing bacteria. Adequate fluid intake is also important to promote saliva production.
Anyone suffering from chronic bad breath should consider a professional dental cleaning and, if necessary, a microbiological examination of the oral flora. If a systemic cause is suspected, a comprehensive internal medical evaluation is recommended.
Role of probiotics and new therapeutic approaches
Interestingly, research is increasingly showing that probiotics can also contribute to the treatment of bad breath. Certain strains, such as Streptococcus salivarius M18, can displace odor-causing bacteria in the mouth. The targeted use of microbiome-friendly dental care products that avoid harsh chemicals is also being discussed as promising.
Conclusion: Education is the first step
Bad breath is not a fate, but a symptom with a usually clearly identifiable cause. Those who educate themselves not only improve their quality of life but also gain confidence in social interactions. A combination of good oral care, a healthy lifestyle, and, if necessary, professional help is crucial. Modern dentistry offers numerous options for effectively diagnosing and treating bad breath. And the sooner the taboo surrounding the topic is removed, the better the causes can be addressed.
