Is Chlorine Dioxide Safe to Use as Mouthwash?

Is Chlorine dioxide really as beneficial as they say? 

There have been many studies that suggest that this chemical is really a multipurpose disinfectant that is even safer than chlorine and bleach. But just how versatile is this disinfectant? 

What is Chlorine Dioxide?

Chlorine Dioxide is a disinfectant, commonly used to purify drinking water. It is very safe in small quantities and can be used in the household for disinfecting produce, cleaning and sterilizing medical equipment, and even in the production of paper making. 

Another excellent household use of chlorine dioxide is as a mouthwash. Now, unlike bleach, chlorine dioxide is also safe to use as a mouthwash. But how exactly should it be used, and how does it help with oral health and hygiene? 

Let’s take a look at what causes these issues to begin with. 

Chlorine vs. Chlorine Dioxide: What’s the Difference?

Some people are concerned by the word chlorine in chlorine dioxide, but despite the similar names, these are very different chemicals.

The only thing chlorine and chlorine dioxide share is part of the name. Their chemical structures and reactions are not the same. Chlorine dioxide contains oxygen, which completely changes how it behaves.

A simple comparison helps explain this difference: hydrogen is a flammable gas, but when it combines with oxygen, it forms water. In the same way, chlorine dioxide is fundamentally different from chlorine.

Chlorine-based products work through chlorination, meaning chlorine is added to organic compounds. Chlorine dioxide works through oxidation, a different process that does not add chlorine to organic materials and does not behave like household bleach or chlorine-based cleaners.

What causes bad oral health?

Oral health and hygiene is essential to the overall health of your body. Poor oral hygiene leads to issues with oral health such as cavities, gum disease, gingivitis and plaque. Some of these issues have also been linked to other health problems such as cancer, diabetes and heart disease. 

Not following good oral hygiene practices can lead to a myriad of oral issues.

Some of these include: 

• Bleeding or swollen gums
• Oral ulcers
• Chronic bad breath
• Receding gums
• Sensitive teeth
• Cracked or broken teeth
• Toothaches and pain

Maintaining good oral health includes the practice of brushing with toothpaste at least twice daily, flossing at least once daily, limiting sugary drinks and foods, and topping off your clean with mouthwash. One ingredient that could really boost mouthwash to give you an ever better clean is chlorine dioxide. 

Is Chlorine Dioxide safe in Mouthwash?

One of the symptoms of poor oral health is chronic bad breath. Chlorine dioxide is known to eliminate the bacteria that cause bad breath, but the big question is, how safe is it for use? 

Odours are caused by compounds that contain sulphur bonds in their molecular structure. Chlorine dioxide is able to safely and effectively break down the volatile sulphur compounds that help to contribute to bad breath. By breaking down these bonds, Chlorine dioxide is able to eliminate their ability to produce odour. 

Studies have shown that Chlorine Dioxide is effective at significantly reducing oral malodour in as little as two weeks after use.

"CONCLUSIONS The results show that a 0.1% ClO2 mouthwash significantly reduces oral malodor and the concentrations of H2S and CH3SH after 12 hr and after 2 weeks. Moreover, this mouthwash is effective in decreasing PI, tongue coating, and the amounts of Gram‐positive and Gram‐negative bacteria such as F. nucleatum, S. moorei, T. denticola, and T. forsythia in saliva. From our results, ClO2 is a promising agent in the treatment and management of bad breath."

Additionally, it is also effective in decreasing tongue coating and the negative bacteria that are key agents in producing bad breath. 

Another positive effect of using Chlorine dioxide as a mouthwash is that it does not have the same burning effect that mouth rinses with alcohol have. This means it is great for people with more sensitive mouths, as it tends to be a lot more gentle. 

How to use Chlorine Dioxide Mouthwash

Directions for Use

1. Measure the amount on the label

• Usually ½–1 capful (10–20 mL)

2. Swish gently

• Swish around the mouth and between teeth for 20–40 seconds.
• No aggressive gargling needed.

3. Spit it out

• Do NOT swallow.

4. Do not rinse with water right away

• Wait 5–10 minutes so it can continue working.

5. Use 1–2 times daily

• Often recommended morning and night.
• Overuse does not improve results and may irritate tissues.

🦷 What it’s commonly used for

• Bad breath (neutralizes sulfur compounds)
• General oral hygiene
• Freshening without alcohol burn (many formulas are alcohol-free)

⚠️ Important safety notes

• Never ingest chlorine dioxide
• Stop use if you feel burning, irritation, or taste changes
• Extra caution for kids/teens → follow dental guidance and product age limits

Common Concentrations Used in Mouthwashes

Many popular mouthwashes on the market contain chlorine dioxide, which is quite common. If your mouthwash lists chlorine dioxide as an ingredient, ensure the concentration does not exceed the recommended limit of 150 milligrams per litre (150 ppm) for safety. Studies indicate that a concentration of 1 to 75 parts per million (ppm) is effective for chlorine dioxide in mouthwash. Effective mouthwashes containing chlorine dioxide (ClO2) typically have a concentration of 10 to 75 ppm, making them suitable for safe daily use by most individuals.

Below are two additional studies, each accompanied by highlighted key points that emphasize their importance.

"Chlorine dioxide is an active ingredient for anti-microbial activity, and is used in oral care products to reduce or eliminate biological activity associated with oral diseases and breath malodor. Chlorine dioxide at an active level of about 1 ppm to about 75 ppm is an effective germicidal in an oral care composition, and chlorine dioxide is an effective and safe germicidal when used in mouthwash and mouth rinse compositions at from about 0.0005% to about 0.2%."

https://patents.google.com/patent/US6582682B2/en

"Based on experimental data and theoretical considerations, we point out that pure chlorine dioxide mouthwash has practically no effect on the mucous membrane, but it does affect the bacterial flora of the oral cavity. According to published data, a significant proportion of bacteria survive oral rinses, and rinsing kills pathogenic microbes more effectively than others. The latter can be explained by colonization resistance. Then, with the help of a model calculation based on the diffusion of ClO2 in plaque, we show that the majority of dental plaque bacteria cannot survive a 15-second mouth rinse with mouthwash containing 15 ppm ClO2. In other words, although the survival of a significant proportion of bacteria is obviously enabled by an oral biofilm, dental plaque cannot do so."

https://chemrxiv.org/doi/pdf/10.26434/chemrxiv-2025-bsnc1

Essentially, Chlorine Dioxide is a powerful tool in the fight against poor oral health and bad breath. So search for mouthwashes that contain chlorine dioxide and enjoy fresh breath!

Ready to try Chlorine Dioxide products? Click here to explore our selection. You’ll also find more detailed information on each product’s page if you want to learn more.

Disclaimer
This information is provided for general educational purposes only and is not intended as medical or dental advice. This product is intended for use only as directed on the label. Do not swallow. Not intended for internal consumption. Individual results may vary. Discontinue use if irritation occurs and consult a qualified dental or healthcare professional if you have questions, pre-existing oral conditions, are pregnant, nursing, or if symptoms persist. Keep out of reach of children.