The main application of sodium chlorite is the generation of chlorine dioxide for bleaching and stripping of textiles, pulp, and paper.

[1]: 25, 33  Chlorine dioxide generated from sodium chlorite is approved by FDA under some conditions for disinfecting water used to wash fruits, vegetables, and poultry.

[2][full citation needed][3] Sodium chlorite, NaClO2, sometimes in combination with zinc chloride, also finds application as a component in therapeutic rinses, mouthwashes,[4][5] toothpastes and gels, mouth sprays, as preservative in eye drops,[6] and in contact lens cleaning solution under the trade name Purite.

[11] The U.S. Army Natick Soldier Research, Development, and Engineering Center produced a portable "no power required" method of generating chlorine dioxide, known as ClO2, gas, described as one of the best biocides available for combating contaminants, which range from benign microbes and food pathogens to Category A Bioterror agents.

In the weeks after the 9/11 attacks when anthrax was sent in letters to public officials, hazardous materials teams used ClO2 to decontaminate the Hart Senate Office Building, and the Brentwood Postal Facility.

Sodium chlorite, like many oxidizing agents, should be protected from inadvertent contamination by organic materials to avoid the formation of an explosive mixture.

From the analogy with sodium chlorate, even small amounts of about 1 gram can be expected to cause nausea, vomiting and even life-threatening hemolysis in glucose-6-phosphate dehydrogenase deficient persons.

[21] Sellers of “Miracle Mineral Solution”, a mixture of sodium chlorite and citric acid also known as "MMS" that is promoted as a cure-all have been convicted, fined, or otherwise disciplined in multiple jurisdictions around the world.

Even hydrogen peroxide can be used as the reducing agent, giving oxygen gas as its byproduct rather than other inorganic salts or materials that could contaminate the desired product.