Is Mouthwash Bad For You? (2024)

Is Mouthwash Bad For You?

Welcome to my blog on mouthwash and whether it is bad for you. I know this might sound a bit crazy and clickbaity but there is extensive research exploring, and demonstrating, that perhaps many of us should be ditching our mouthwashes.

The Importance Of The Oral Microbiome

You may like to read my blog on the Oral Health: A Key Determinant In Health.

The oral cavity can be regarded as the mirror of systemic health, since many systemic diseases may have manifestations in the oral cavity, as in the case, among oral, potentially malignant disorders, and, vice-versa, oral diseases may affect systemic health, impairing patient’s nutrition and wellbeing, reducing the quality of life and increasing stress and anxiety.

Worldwide, oral diseases affect 3.5 billion individuals, and oral and lip cancers rank among the 15 most common oral diseases, with potential repercussions on the systemic health of patients. In this perspective, the World Health Organization recognises oral health as a “key indicator of overall health, well-being and quality of life” and it shares “modifiable risk factors with the leading noncommunicable diseases (cardiovascular diseases, cancer, chronic respiratory diseases and diabetes)”. An emblematic example is the bi-directional link between diabetes and periodontitis.

Strategies to prevent and treat periodontitis should consider a multi-factorial and multi-disciplinary approach, in the perspective of a personalised medicine and of a holistic view; for example, physical exercise, along with nutritional counselling, is a cornerstone in the treatment and prevention of type 2 diabetes, but it can also reduce the prevalence of cardiovascular risk and of periodontal disease

The Nitrate-Nitrite-Nitric Oxide Pathway

This pathway is a well researched link between what we eat, our oral microbiome, and our systemic health.

Dietary nitrate can be found in vegetables, especially in leafy greens (lettuce, kale and spinach) and beetroots. It can also be found in processed meats for flavouring, preservation and antimicrobial purposes. There is some evidence that suggests nitrate added to processed meats can lead to the production of carcinogenic compounds. However, around 80% of dietary nitrate is obtained from vegetables which are considered anti-carcinogenic. Unless your carnivore of course!

It is clear in the research that plant-based nitrate provides positive effects on both oral and systemic health. This is because nitrate consumption leads to the production of nitric oxide (NO), which is associated with numerous facets of health including our immune system, nerve to nerve communication, improved vascular and metabolic health, and improved exercise performance.

Noteworthy is that nitric oxide is a potent vasodilator and as a result regulates blood pressure and blood flow. It has been shown in the research that high nitrate diets are associated with a reduced risk of cardiovascular disease (CVD), diabetes and cognitive impairment. This makes totally sense nitric oxide will support the delivery of oxygen and nutrients to our cells – and cells need these things to function properly.

Interestingly, nitric oxide can also be produced endogenously from L-arginine and NADPH in an oxygen-dependent reaction involving nitric oxide synthase enzymes (NOS), of which there are three main types (endothelial NOS (eNOS), inducible NOS (iNOS) and neuronal NOS (nNOS)). Unfortunately, endogenous nitric oxide production becomes less efficient with age. However, dietary nitrate  is reduced to nitric oxide via the nitrate-nitrite-nitric oxide pathway.

Where does the oral microbiome come in to this?

This process is facilitated by nitrate-reducing bacteria (NRB) inside the oral cavity, including Rothia and Neisseria, which are associated with positive oral health. High-nitrate diets have been shown to increase health-associated genera and decrease the number of disease-associated bacteria. (source)

The Impact Of Mouthwash

There have been a suprising number of studies looking at this. The most common mouthwash investigated are those that include chlorhexidine, which is a commonly used mouthwash with potent anti-microbial effects useful for the management of oral disease. However, just your ‘over-the-counter- mouthwash with alcohol has been shown to have negative effects on the oral microbiome.

We are also moving away from the view of simply ‘killing’ bacteria, towards managing oral microbial ecosystems (oral microbiome), as an integrated system, to promote oral and systemic health. Researchers have aimed to review the effects of chlorhexidine mouthwash on the balance of microbial communities in the mouth in vivo in oral health and disease.

They found that chlorhexidine causes a shift towards lower bacterial diversity and abundance, in particular nitrate-reducing bacteria in vivo. Chlorhexidine also appeared to alter salivary pH, lactate, nitrate and nitrite concentrations in saliva.

The paper concluded: “Chlorhexidine alters the composition the oral microbiome. However, as Chlorhexidine use remains widespread in dentistry to manage oral disease, urgent research using metagenomics studies of microbial communities in vivo are still needed to determine Chlorhexidine mouthwash is ‘good’, ‘bad’ or otherwise for bacteria, in the context of oral and systemic health”. (source) But they would say that – this paper is in the Journal Of Dentistry (I kinda assume they’re going to take a more cautious approach here as some stand to be financially effected by a change to their current management of oral health.

The Best Mouthwash For Oral Health

The Best Toothpaste For Oral Health


It seems pretty clear that the majority of us should ditch our over the counter mouthwashes if we want to ensure a healthy oral microbiome, and support our overall health. Consuming nitrate rich foods such as spinach and other dark green leafy vegetables, as well as beetroot may support a healthy microbiome also.

Alex Manos Profile 2015 AM Logo scaled

Alex is a certified Functional Medicine Practitioner (IFMCP) and has a MSc in Personalised Nutrition. He is also a breathwork facilitator with a background in personal training and massage therapy. He also runs The Resiliency Program - a 24 week program aimed at building physical, mental, emotional, and spiritual resilience.

Share this post