Chlorine dioxide is a strong anti-infectious agent. It is antibacterial, antiviral, and can help improve oral health. Read more to learn about the health benefits and side effects of chlorine dioxide.

What is Chlorine Dioxide?

Chlorine dioxide (ClO2) is a yellow-green gas that was discovered in 1814. Since the early 1900s, people have been using it as a disinfectant [1, 2].

Chlorine dioxide is an oxidant. This means that chlorine dioxide removes electrons from another compound during a chemical reaction [2].

Chlorine dioxide is antimicrobial, antibacterial, and antifungal [3].

Since chlorine dioxide is a gas, it can easily penetrate and disintegrate pathogens [4].


Chlorine dioxide acts as an oxidizing agent (gains electrons during chemical reactions) and interacts with cell components [5].

By taking electrons from microbes, the microbe’s molecular bonds weaken and the cell breaks apart. This process alters the proteins involved in their structure and decreases enzyme function, thus resulting in the death of the microbe [5].

This attack on many proteins simultaneously prevents the microorganisms from mutating to a resistant form [6].

Uses of Chlorine Dioxide

1) Chlorine Dioxide Is Antibacterial and Antifungal

Chlorine dioxide gas can go through bacterial cell membranes and cause cell death in the pH range of 3-9 [4, 7].

In lab tests, chlorine dioxide was more effective at inactivating fungal spores than chlorine. It inactivated fungal spores by damaging the cell wall and cell membrane, thus causing the leakage of cell substances and eventually, fungal death [8].

In another study, a chlorine dioxide solution reduced 98.2% of bacteria and fungi in a lab test (E. coli, Staphylococcus, Pseudomonas, listeria, salmonella, Candida albicans, etc) [3].

2) Chlorine Dioxide Is a Powerful Disinfectant

The antimicrobial properties of chlorine dioxide are used to disinfect food, surgical tools, and more [9, 10, 8].

Low concentrations of chlorine dioxide are effective in reducing E. coli present in water. Various chlorine dioxide products can help disinfect water and produce safe drinking water [11].

In a 30-month (prospective) study, chlorine dioxide-treated water in a hospital decreased Legionella bacteria counts. Additionally, there were no patients that acquired Legionnaires disease during the study [12].

The bacteria on vegetable seed sprouts can cause stomach problems and disease outbreaks. Chlorine dioxide treatment and dry heating eliminated E. coli on radish seeds without damaging the seeds. Thus, it can help with food safety [10].

Chlorine dioxide treated-water significantly reduced Escherichia coli (E.Coli) bacteria counts on baby spinach. However, non-culturable cells (bacteria that does not grow or divide) were still present. The treatment did not affect the quality of the baby spinach, but it reduced its photosynthetic abilities [11].

In a pilot study, chlorine dioxide gas disinfected gastrointestinal endoscopes, an instrument used to look at the inside lining of the digestive tract. The gas completely inactivated bacterial cells and disinfected all endoscopes [9].

3) Chlorine Dioxide Sterilizes the Air

Chlorine dioxide gas efficiently disinfected and improved air quality indoors after single (0.28L solution, 250 mg/L), double, and triple doses. All three doses reduced indoor bacteria and fungi concentrations, but the double and triple doses had significantly better antimicrobial effects [13].

In another study, a chlorine dioxide-based agent was more effective than hydrogen peroxide at killing bacteria that had enhanced resistance to chemical and radiation disinfection (B. pumilus SAFR-032 and Bacillus subtilis ATCC 6051). Chlorine dioxide can help sterilize peroxide- and UV-resistant spores in hospital environments [14].

In another study, chlorine dioxide decontaminated known pathogens that can cause infections in a hospital room. Although each hospital room had lower bacteria counts, 2 cleaning cycles failed to completely inactivate all harmful organisms [15].

4) Chlorine Dioxide Improves Oral and Dental Health

In a week-long study (DB-RCT) of 15 subjects, a mouthwash containing chlorine dioxide decreased bad breath (more than the placebo). It also reduced the number of chemical compounds with distinct bad smells (hydrogen sulfide, methyl mercaptan, and dimethyl sulfide) [16].

The chlorine dioxide mouthwash also reduced plaque and bacteria that cause gum disease (Fusobacterium nucleatum) in saliva [16].

In another study (TB-RCT) of 25 healthy subjects, mouthwash containing chlorine dioxide was as effective as an antibacterial mouthwash (chlorhexidine). There was no significant difference in plaque concentration or bacteria count. Although the chlorhexidine mouthwash initially had a lower bacteria count, there was no statistically significant difference [17].

Chlorine dioxide may also help whiten teeth. It was faster at whitening cow teeth than hydrogen peroxide. However, since it has a low pH, long-term exposure may harm teeth [18].

A 5% chlorine dioxide solution can also help clean the mouth during root canals due to its antimicrobial properties [4].

5) Chlorine Dioxide Is Antiviral

Chlorine dioxide is also antiviral. It destroys the proteins on the outside of viruses and degrades the virus [19].

Chlorine dioxide gas is effective against [20]:

  • Human influenza (IFV)
  • Measles
  • Human herpes (HHV)
  • Human adenovirus (HAdVs)
  • Influenza A (in mice) [19]

Chlorine dioxide solution also inactivated human and monkey rotaviruses (that cause diarrhea) and hepatitis A [21, 22].

Negative Effects of Chlorine Dioxide

1) Chlorine Dioxide Gas Damages Proteins and Cells

Normally, exposure to low amounts of chlorine dioxide is safe. In a study of 17 dialysis patients, 1 month of exposure to chlorine dioxide-treated water did not have any toxic effects or cause anemia (low red blood cell levels) [23].

However, in rats, chlorine dioxide gas altered the structure of blood cells and prevented DNA formation in several organs. The changes in blood cells caused mild hemolytic anemia, a condition in which blood cells are destroyed and removed before their normal lifespan is over [24].

Additionally, an oral dose of 14 mg in rats reduced proteins in their brain cells and had the neurotoxic potential [25].

2) Chlorine Dioxide Impurities are Harmful to Health

Chlorine dioxide products also contain high levels of impurities (reactants with additional compounds). These products are useful for wastewater treatment but dangerous when in contact with humans or food [26].

Impurities are mainly caused by its chlorine dioxide’s products, such as chlorine and chloroxy anion (ClO2−or ClO3−). They can react with organic matter to form trihalomethane, a compound that causes cancer (carcinogen) [24].

Limitations and Caveats

There are only a few human studies available on the effects of chlorine dioxide.

Humans who have a higher sensitivity to chemicals may have negative reactions to chlorine dioxide [27].

People with G6PD deficiency may have a higher risk of developing anemia due to chlorite exposure from chlorine dioxide [23].

More studies should be performed before you use chlorine dioxide disinfectants in your daily life.


Chlorine dioxide is unstable as a gas and is explosive in concentrations greater than 10%. It can be ignited by almost any form of energy, including sunlight and heat [28, 29].

Chlorine dioxide is toxic and can burn or severely irritate the skin and eyes in high concentrations [30].

The Occupational Safety and Health Administration states that the highest exposure to chlorine dioxide in the air should be 0.1 ppm and 0.3 mg/m3 [31].

There has been a rare case of kidney damage in a man who drank 250 mL of chlorine dioxide [32].

Drug Interactions

Diclofenac is a drug that treats pain, arthritis, and migraines (NSAID). In water, chlorine dioxide can degrade diclofenac. While this is beneficial during water treatment, its effects on the human body are unknown [33].


Chlorine dioxide can be found in a gaseous, liquid, or solid state [34, 30, 35].

The best way to store chlorine dioxide is as a liquid/ dissolved gas at 4 ºC. Chlorine dioxide cannot be stored for too long, because it slowly separates into chlorine and oxygen [36].

Miracle Mineral Solution

Miracle Mineral Solution is a product that contains sodium chlorite. To use it, you mix 3 drops with an acidic solution, such as lemon juice, to make chlorine dioxide. The creator claimed that it can cure AIDS, cancer, hepatitis, malaria, and autism [37].

However, it has none of those benefits. Instead, it can cause health problems such as [37]:

  • Nausea
  • Dehydration
  • Severe vomiting
  • Diarrhea
  • Low blood pressure (hypotension)
  • Death

In one case, a patient developed Kikuchi-Fujimoto disease after drinking an unknown amount of the miracle mineral solution. The solution triggered an inflammatory response and caused fever, night sweats, and swollen lymph nodes [37].

It is banned in the US, UK, and Canada. Do not use this product to treat any disease.

User Experiences

Various users commented that chlorine dioxide was good at disinfecting water. They did not have any stomach issues when using the treatment, and it was faster than other water treatment processes.

One user said that chlorine dioxide mouthwash made their mouth feel less filthy and grimy. Their breath was fresher and cleaner.

A user praised 2% chlorine dioxide for killing microbes that were present in the air. They said that it was cost-effective, safe, and powerful.

However, other reviewers were wary about the possible skin burns and eye damage from chlorine dioxide water treatment.

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