Antibiotics work against pathogenic bacteria – this is often medically necessary and, in many cases, life-saving. However, these drugs do not distinguish between "good" and "bad" bacteria. They destroy the microbial diversity throughout the body, including the oral cavity. The result: The oral microbiome , a complex community of over 700 known microorganism species, is weakened or even permanently disrupted.
After antibiotic treatment, it can take weeks or even months for the natural oral flora to regenerate. During this phase, the oral cavity is particularly vulnerable to fungal infections, gingivitis, bad breath, tooth decay, and other oral diseases. Failure to take action risks long-term damage.
But there is hope: targeted probiotics – especially Streptococcus salivarius M18 – can actively support the development of oral flora.
Understanding the oral microbiome
The oral microbiome is more than just a collection of bacteria. It is a highly sensitive ecosystem that interacts with the immune system, controls inflammatory processes, protects against pathogens, and maintains physiological balance in the oral cavity. A healthy biofilm on the tongue, teeth, and gums prevents the penetration of pathogenic germs such as Candida albicans or Streptococcus mutans .
Antibiotics damage this biofilm. Protective bacterial strains are wiped out, while pathogenic microbes such as fungi or aggressive bacterial species occupy the resulting gaps. Therefore, rebuilding the oral flora requires targeted support.
What are oral probiotics – and why are they so important after antibiotics?
Probiotics are living microorganisms that, when consumed in sufficient quantities, have a health-promoting effect on the body. While most probiotics target the intestinal flora, there are special oral probiotics that act directly in the oral cavity.
These special strains of bacteria can:
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displace pathogenic germs,
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stimulate the immune system in the mouth,
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regulate saliva pH,
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Prevent caries and periodontitis,
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and restore the oral biofilm structure.
One of the most effective and scientifically well-studied oral probiotics is Streptococcus salivarius M18 .
Streptococcus salivarius M18: The key to healthy oral flora
Streptococcus salivarius M18 is a naturally occurring bacterial strain originally discovered in the saliva of healthy humans. It is known to actively contribute to maintaining a healthy oral environment.
Why is S. salivarius M18 so special?
It has a unique combination of health-promoting properties:
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Production of bacteriocins (natural antibiotics) that inhibit pathogenic bacteria such as Streptococcus mutans
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Formation of enzymes such as dextranases , which can dissolve plaque
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Supports the remineralization of tooth enamel
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Restoring saliva balance by regulating pH
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Formation of a protective biofilm that prevents the settlement of pathogenic germs
Numerous studies demonstrate the effectiveness of Streptococcus salivarius M18 in the prevention of caries, gingivitis and bad breath – especially after medical procedures or medications that affect the oral flora.
How long does it take to rebuild the oral flora after antibiotics?
The duration varies from person to person but depends on several factors:
| factor | Influence on regeneration |
|---|---|
| Duration of antibiotic therapy | Longer treatments destroy more microbiota |
| Type of antibiotic | Broad-spectrum antibiotics have a stronger effect on the flora |
| Diet | A diet rich in sugar inhibits regeneration |
| Immune status | A weakened immune system delays the development |
| Use of oral probiotics | Accelerates recolonization with “good” germs |
| Oral hygiene | Mild but consistent treatment supports recovery |
Without targeted measures, it can take up to six months for the oral flora to fully return to normal. With accompanying probiotic therapy, this period can be significantly shortened.
How to support your oral flora after antibiotics
After antibiotic treatment, you should take action to restore your oral flora to balance. Here are the most effective strategies:
1. Take probiotic lozenges with Streptococcus salivarius M18
Products containing S. salivarius M18 (e.g., BLIS M18 , K12+M18 combinations ) are specifically developed for oral use. They are ideally sucked in the evening after brushing your teeth , allowing the bacteria to colonize directly in the oral cavity.
2. Reduce sugar and integrate fermented foods
Sugar promotes the growth of pathogenic bacteria and inhibits regeneration. A probiotic-friendly diet includes fiber-rich, fermented foods such as sauerkraut, miso, kombucha, or natural yogurt – these also support overall microbial diversity.
3. Use mild oral care products
Many conventional toothpastes and mouthwashes contain harsh antimicrobial agents like triclosan or alcohol, which can further weaken the oral microbiome. Instead, use products containing:
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Xylitol (inhibits caries bacteria),
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enzymes,
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plant bioflavonoids,
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or even additional probiotics.
4. Don’t forget to clean your tongue
The tongue is a primary habitat for microorganisms. Regular tongue cleaning helps reduce pathogenic biofilms and promote colonization by beneficial bacteria.
5. Stress reduction and sufficient sleep
Stress weakens mucosal barriers and reduces the immune system in the mouth. Ensure adequate sleep and stress management to support the regeneration of your microbiome.
Scientific studies on Streptococcus salivarius M18
Research on the effects of oral probiotics—especially S. salivarius M18—is steadily growing. Here's an overview of some insightful study results:
| Study / Source | Result |
|---|---|
| Burton et al., 2013 | Reduction of plaque and gingivitis after 3 weeks of taking BLIS M18 |
| Di Pierro et al., 2015 | Significant improvement of halitosis symptoms by S. salivarius M18 |
| Ishikawa et al., 2021 | Detection of S. salivarius M18 colonization in the oral biofilm structure |
| Guglielmetti et al., 2010 | Improved oral health in children with frequent antibiotic use |
These studies confirm that probiotic intervention with M18 not only shows a short-term effect, but can lay the foundation for long-term oral resilience .
Conclusion: Your oral flora needs targeted help – and probiotics offer it
Taking antibiotics leaves its mark on the body—especially in the delicate ecosystem of the oral cavity. Without targeted support, this can lead to permanent damage, manifesting as caries, periodontitis, or fungal infections.
With targeted oral probiotics—especially Streptococcus salivarius M18—you can restore balance to your oral flora . Combined with a proper diet, gentle oral care, and a healthy lifestyle, this can strengthen not only your oral health but also your overall health in the long term.
FAQ – Frequently asked questions on the topic
How long should you take probiotics after antibiotics?
At least 4–6 weeks, 8 weeks is optimal to promote stable colonization of the bacteria.
Are probiotics also useful while taking antibiotics?
Yes, but they should be taken at different times (at least 2-3 hours after the antibiotic) so as not to neutralize the effect.
Can Streptococcus salivarius M18 and K12 be combined?
Yes. K12 works more in the throat and supports the immune system, while M18 is active in the mouth against caries bacteria. Together, they are particularly effective.
