Side Effects of Listerine Mouthwash
Listerine mouthwash is a popular choice for maintaining oral hygiene. However, like any product, it can have side effects. Knowing these effects, including its impact on oral bacteria, is crucial for making informed decisions about its use.
Common Side Effects
Burning Sensation
One of the most commonly reported side effects of using Listerine mouthwash is a burning sensation in the mouth. This is primarily due to the presence of alcohol and essential oils like menthol, thymol, and eucalyptol, which can cause irritation, especially if you have sensitive oral tissues.
Dry Mouth
Listerine mouthwash, particularly those containing alcohol, can contribute to dry mouth (xerostomia). Alcohol can reduce saliva production, leading to a feeling of dryness in the mouth. This can be particularly problematic for individuals who already suffer from dry mouth.
Canker Sores
The ingredient sodium lauryl sulfate (SLS), found in some oral care products, can irritate the lining of the mouth and potentially cause or exacerbate canker sores. While not all Listerine products contain SLS, those that do may pose this risk.
Impact on Oral Bacteria
Killing Good and Bad Bacteria
Listerine mouthwash is known for its powerful antibacterial properties. It can kill up to 99.9% of bacteria in the mouth. However, this broad-spectrum action means it doesn’t discriminate between harmful and beneficial bacteria.
Good Bacteria: Your mouth contains a delicate balance of good and bad bacteria. These good bacteria help to defend your body against pathogens. Some beneficial bacteria in the mouth aid in digestion and protect against harmful microbes in food.
Bad Bacteria: Listerine is effective against several harmful bacteria, including:
- Streptococcus mutans: Responsible for tooth decay
- Porphyromonas gingivalis: Associated with gum disease
- Treponema denticola: Linked to bad breath
- Prevotella intermedia: Another contributor to gum disease.
While eliminating these harmful bacteria is beneficial, the indiscriminate killing of both good and bad bacteria can potentially disrupt the oral microbiome’s balance.
Effectiveness Against Oral Pathogens
Research has shown that Listerine can completely kill microorganisms in 10 to 30 seconds, including methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Helicobacter pylori, Candida albicans, and various oral pathogens. This broad-spectrum antimicrobial action contributes to its effectiveness in preventing gingivitis and reducing plaque.
Considerations for Use
Balancing Benefits and Risks
While Listerine’s ability to kill harmful bacteria is beneficial for oral health, its impact on the overall oral microbiome should be considered. Some experts suggest that promoting the growth of good bacteria may be as important as eliminating bad bacteria for oral health.
Alternatives and Moderation
For those concerned about disrupting their oral microbiome, consider:
- Using alcohol-free versions of Listerine
- Limiting the frequency of use
- Exploring probiotic mouthwashes (though evidence on their effectiveness is limited)[5]
Who Should Be Cautious
Certain individuals should be cautious or avoid using Listerine mouthwash:
- Children under 6 years old
- People with mouth sores
- Chemotherapy patients
- Those with known allergies to ingredients
Proper Use of Listerine Mouthwash
To maximise benefits and minimise side effects:
- Measure 20 millilitres (4 teaspoons) of mouthwash
- Swish for 30 seconds
- Spit out, do not swallow
Understanding the side effects of Listerine mouthwash, including its impact on oral bacteria, can help you make informed decisions about its use in your oral care routine. While it’s effective at killing harmful bacteria, its broad-spectrum action may affect the overall balance of your oral microbiome. As with any oral care product, it’s best to use Listerine as directed and consult with a dental professional if you have concerns about its effects on your oral health.