Is Chlorine Dioxde Use Pseudoscience?

This is a response to an opinion article on Frontiers titled, Pseudoscience in the Times of Crisis: How and Why Chlorine Dioxide Consumption Became Popular in Latin America During the COVID-19 Pandemic.

At the beginning of the frontiers article, the author provides misleading and extremely distorted information about Chlorine Dioxide and commits the straw man fallacy.

This response to the frontiers article will address the three misleading and distorted statements made by the author regarding the safety and effectiveness of Chlorine Dioxide. Then this response will provide the reader with a review of the scientific literature regarding the safety and effectiveness of chlorine dioxide within the proper context.

First, I will list the quoted statements from the frontiers paper that will be addressed:

1. “At high concentrations and non-physiological pH, chlorine dioxide effectively inhibits microbial and viral activity (Hauchman et al., 1986; Zoffoli et al., 2005).”

2. “Exposure to high doses of chlorine dioxide has been shown to cause thyroid suppression, DNA damage and neurotoxicity in several animal models”

3. “It is therefore understood that chlorine dioxide is not safe for human consumption.”

The three statements are inaccurate and distorted because they provide the reader with very limited information about a substance that has been well researched and thoroughly understood concerning safety, efficacy, and toxicity. The author withheld or was ignorant of vital published literature about the subject. By omitting crucial information that completely falsifies the conclusion, the reader is led to believe that “chlorine dioxide is not “safe for human consumption.”

Let’s look at the three inaccurate and distorted statements in light of the published scientific literature that was not included. The first inaccurate and distorted statement was, “At high concentrations and non-physiological pH, chlorine dioxide effectively inhibits microbial and viral activity.” This statement is only half of the truth. What was not mentioned is that chlorine dioxide also effectively inhibits microbial and viral activity at low concentrations and physiologically compatible pH. The fact that chlorine dioxide is bactericidal and viricidal at low concentrations and has a physiologically compatible pH is why it is used to treat drinking water immediately before use. It is also why many consumer products contain chlorine dioxide and are readily available for purchase. The author’s statement is deceptive and has significant implications. It may cause the reader to assume that chlorine dioxide would not inhibit microbial and viral activity within ranges safe for human consumption.

Chlorine dioxide is an effective virucide and bactericide at low concentrations and biologically compatible pH

From Drinking Water and Health, Vol. 2 it states, “The bactericidal activity of chlorine dioxide was not affected by pH values from 6.0 to 10.0. Ridenour and Armbruster (1949) extended their observation to other enteric bacteria. The common waterborne pathogens were similarly inactivated with chlorine dioxide.” (p 56). The book also states, “Greater than 99% inactivation of E. coli was observed in 15 s with 0.25 mg/liter (0.25 ppm) chlorine dioxide.” (p 57) Drinking Water and Health, Vol 2, pg. 56-57.

Chlorine dioxide’s effectiveness at low concentrations is not limited to bacteria; rather, it has an equal if not more significant viricidal effect. “Chlorine dioxide gas solution at concentrations ranging from 1 to 100 ppm inactivated ≥99.9% of viruses, such as feline calicivirus, human influenza virus, measles virus, canine distemper virus, human herpesvirus, human adenovirus, canine adenovirus, and canine parvovirus within 15 s and the antiviral activity was about 10 times higher when compared to sodium hypochlorite” Sanekata, T., Fukuda, T., Miura, T., Morino, H., Lee, C., Maeda, K., & Shibata, T. (2010). Evaluation of the antiviral activity of chlorine dioxide and sodium hypochlorite against feline, human adenovirus, canine adenovirus and canine parvovirus. Biocontrol Science15, 45–49.

Now let’s take a look at the second and third misleading and distorted statements simultaneously. The author of the Frontiers article stated, “Exposure to high doses of chlorine dioxide has been shown to cause thyroid suppression, DNA damage and neurotoxicity in several animal models.” Then the author stated, “It is therefore understood that chlorine dioxide is not safe for human consumption.”

Safe at low concentrations and low doses

The author qualifies the first statement, with the words “high” concentrations and “high” doses. It is well known that many drugs at high concentrations and high doses will have adverse side effects which may be detrimental to human health. In the author’s final statement, the following declaration is made, “it is therefore understood that Chlorine Dioxide is not safe for human consumption.” This statement is completely false, and to be true, the statement should have been written as follows “it is therefore understood that high concentrations and high doses of chlorine dioxide are not safe for human consumption.

The scientific literature proves Chlorine Dioxide is safe for oral human consumption at low therapeutic doses, typically less than 3 mg/kg/day.

In an acute rising dose tolerance test, subjects were given daily doses of chlorine dioxide, with the final maximum amount being 24 mg of chlorine dioxide in 1 liter of water. (24 ppm). The following quote is from the study. “The absence of physiological complications in response to acute single dose administration of chlorine dioxide and its byproducts to normal healthy adult males was demonstrated over a wide range of concentrations.” Lubbers, J. R., and Bianchine, J. R. The effects of the acute rising dose administration of chlorine dioxide, chlorate and chlorite to normal healthy adult male volunteers. J. Environ. Pathol. Toxicol. 5 (2, 3): 865-878 (1982).

In a three-phase trial, subjects were given daily doses of 500 ml of chlorine dioxide 5mg/l (5 ppm). Results: “The three phases of this controlled double-blind clinical evaluation of chlorine dioxide and its potential metabolites in human male volunteer subjects were completed uneventfully. There were no obvious undesirable clinical sequellae noted by any of the participating subjects or by the observing medical team.” Lubbers J, Chauan S, Bianchine J (1982) Controlled clinical evaluations of chlorine dioxide, chlorite and chlorate in man. Environmental health perspectives, 46:57–62.

“An epidemiologic study of 198 persons exposed for 3 months to drinking water disinfected with chlorine dioxide was conducted in a rural village. A control population of 118 nonexposed persons was also studied. Pre-exposure hematologic and serum chemical parameters were compared with test results after 115 days of exposure. Chlorite ion levels in the water averaged approximately 5 ppm during the study period. Statistical analysis (ANOVA) of the data failed to identify any significant exposure­ related effects.” G E Michael et al. Arch Environ Health. Jan-Feb 1981. In the same study, it was mentioned, “Long-term studies in rats consuming water containing 100 mg/L had no apparent effects.”

In the Center for Disease Control’s toxicological profile for chlorine dioxide, it states, “Animal studies indicate that the lowest observed adverse effect level (LOAEL) is approximately 5 mg/kg/day for repeated oral exposure to chlorite.” (Section 2.2, p 10)

In the Environmental Protection Agency registration eligibility decision on chlorine dioxide, it is listed under dietary that the lowest observed adverse effect level (LOAEL) is 6 mg/kg/day. A chronic use endpoint and the no observed adverse effect level (NOAEL) would be 3 mg/kg/day. “The chronic dietary endpoint is 3 mg/kg/day, based on decreases in absolute brain and liver weight, and lowered auditory startle amplitude at LOAEL of 6 mg/kg/day in a two-generation reproduction toxicity study and is supported by a developmental toxicity study in rats.” (EPA 738-R-06-007, p 8)

Subchronic toxicities of ClO2, NaClO2, NaClO3, and NH2Cl were studied in the African Green monkeys (Cercopithecus aethiops). “The chemicals were administered in drinking water during 30-60 days subchronic rising dose protocols. The only unexpected and significant toxic effect was elicited by ClO2; this chemical inhibited thyroid metabolism in the animals at a dose of ca. 9.0 mg/kg/day. A statistically significant decrease of serum thyroxine occurred after the fourth week of exposure to 100 mg/l.concentration.” Bercz J.P., Jones L., Garner L., Murray D., Ludwig D.A., Boston J. Subchronic toxicity of chlorine dioxide and related compounds in drinking water in the nonhuman primate. Environ. Health Perspect. 1982;46:47–55.

Per the above, it is established that the LOAEL is 6 mg/kg/day and NOAEL 3 mg/kg/day, thus showing that low doses at low concentrations are entirely safe. (EPA 738-R-06-007, p 8)

Chlorine Dioxide Dose Calculation for Clarity

For the readers that may not understand what 3 mg/kg/day is in practical terms, I will explain with an example. If we have a 70 kg individual, we would determine the total daily safe dose by multiplying weight, 70 (kg) x 3 (mg), which is 210 mg/day. This person’s daily safe cumulative dosage would be 210 mg/day. If this 70 kg person were taking chlorine dioxide to eliminate, for instance, a urinary tract infection, they would use a general dosing protocol (protocol C) that would consist of taking 1.5 liters of 60 ppm (60 mg/liter) divided into ten equal doses throughout the day. So the person would consume a daily total of 90 mg daily, and it would take approximately 1-3 days to eliminate the infection. This person would be consuming less than half of the amount that is needed to reach the (NOAEL) no observed adverse effect level, and the (LOAEL) lowest observed adverse effect level would be 6 mg/kg/day or 70 (kg) x 6 (mg)= 420 mg/day. The 90 mg daily dose is over four times lower than the lowest observed adverse effect level.


I would encourage your readers to take some time to investigate for themselves as I did. I have chronicled my journey of discovery concerning chlorine dioxide in a documentary titled “The Universal Antidote: The Science and Story of Chlorine Dioxide,” which can be viewed for free at The Universal Antidote Website.

As shown from the literature and multiple studies, chlorine dioxide is both safe and effective at low doses and low concentrations, and it may be unsafe at high doses and high concentrations. I hope that this brief response and rebuttal will encourage further open discussion and clinical research so that chlorine dioxide may be better understood and mankind can receive the full benefit of this fascinating molecule.