Benzalkonium Chloride (BKC) Explained: Uses, Safety, and Side Effects

What is the pharmacology and toxicology of Benzalkonium chloride（BKC）?

Benzalkonium chloride（BKC） solution is a cationic surfactant, which is a broad-spectrum bactericide, which can change the permeability of bacterial cytoplasmic membrane, make bacterial cytoplasmic substances extravasate, hinder its metabolism and play a killing role. Benzalkonium chloride has a strong effect on gram-positive bacteria, but is ineffective against Pseudomonas aeruginosa, acid-fast bacilli and cell spores, and can rapidly combine with proteins. Occasionally, blood, cotton, cellulose and organic matter exist, and the effect is significantly reduced.

Is benzalkonium chloride safe？

Experts in the United States have found that concentrations of benzalkonium chloride less than 0.1% are safe as an ingredient in skin care products, but when the concentration exceeds 0.1%, benzalkonium chloride may be irritating to the skin and eyes. For adults with healthy skin and no wounds on the skin surface, there is no need to worry that this substance will cause harm to the human body when using wet wipes containing benzalkonium chloride with a concentration of less than 0.1%.

What is benzalkonium chloride’s side effects?

As we all know, benzalkonium chloride is currently widely used for cleaning life. Has been identified as a harmful substance or allergen to human skin and respiratory system. The Environmental Cooperation Group (EWG) rated its risk level as 6 points (total of 10 points, 1-2 as low risk, 3-6 as medium risk, 7-10 as high risk), and considered it to be very risky. Patients with breathing problems and people with allergic skin present certain threats.

What is benzalkonium chloride used for?

Benzalkonium chloride（BKC） solution is mainly used for disinfection

✅ Primary Applications

Benzalkonium chloride (BKC) solution is primarily used as a disinfectant for:

• Surgical site mucous membranes

• Skin wounds and mucosal injuries

• Vaginal irrigation in specific medical contexts

⚠️ Note: BKC is for external use only. It must not be used orally, for enemas, or applied over large areas of inflamed or damaged mucosa. Prolonged or excessive use should be avoided.

⚠️ Important Warnings When Using BKC

• Limited efficacy as instrument disinfectant:
  As a quaternary ammonium compound, BKC has moderate bactericidal strength. It is not suitable for sterilizing surgical instruments or heat-sensitive items. Since 2010, safer and more effective alternatives have been recommended.

• Not for use with soft contact lenses:
  BKC should not be used on the mucous surfaces of soft contact lenses due to potential irritation.

• Risk of microbial contamination:
  Aqueous BKC solutions may be contaminated by microorganisms. To reduce this risk:

  • Use aseptic techniques

  • Dilute only before use

  • Prepare fresh solutions when needed

  • Store properly to avoid contamination

• Avoid incompatible substances and materials:

  • Do not mix with soap, salts, or synthetic detergents

  • Do not store in polyvinyl chloride (PVC) bottles to prevent reaction with plasticizers

  • Avoid aluminum containers

  • When disinfecting metal instruments, add 0.5% sodium nitrite to prevent rust

• Not suitable for certain devices:
  BKC is not recommended for disinfecting:

  • Cystoscopes

  • Ophthalmic instruments

  • Synthetic rubber products

❗ Side Effects of Benzalkonium Chloride in Medical Use

• Skin & Eye Reactions:
  While low concentrations generally do not cause irritation, repeated use can lead to allergic reactions, especially in sensitive individuals.
  As an eye drop preservative, BKC has been linked to:

  • Allergic conjunctivitis

  • Corneal epithelial damage

  • Vision disturbances or loss

• Systemic Toxicity (in rare misuse cases):
  BKC has depolarizing muscle relaxant effects. Accidental ingestion or improper use may cause:

  • Respiratory muscle paralysis

  • Dyspnea, cyanosis, suffocation

  • Central nervous system depression

  • Hypotension, coma, or death

Benzalkonium chloride（BKC） is used as an antibacterial in water treatment

Benzalkonium Chloride is a cationic surfactant, a non-oxidizing fungicide, with broad-spectrum and high-efficiency sterilization and algae killing ability, can effectively control bacteria and algae reproduction and slime growth in water, and has good slime peeling It has certain dispersing and osmotic effects and has certain degreasing, deodorizing and corrosion-inhibiting effects.

Benzalkonium chloride has low toxicity, no cumulative toxicity is easily soluble in water and is not affected by water hardness, so it is widely used in circulating cooling water systems in petroleum, chemical, electric power, textile, and other industries. Paper mills and oil well water injection systems in oil fields are used to control the growth of bacteria and algae in circulating cooling water systems and are useful for killing sulfate-reducing bacteria. Benzalkonium chloride is used as a bactericidal and algicide, and the general dosage is 50-100mg/L; as a slime stripper, the dosage is 200-300mg/L, and an appropriate amount of silicone antifoaming agent can be added when necessary.

Benzalkonium chloride can be used in combination with other fungicides,

such as isothiazolinone, glutaraldehyde, dithiocyanomethane, etc., which can play a synergistic effect but cannot be used together with chlorophenols. After the addition of benzalkonium chloride, there is dirt in the circulating water due to peeling, which should be filtered or removed in time to avoid deposition after the foam disappears. Benzalkonium chloride should not be mixed with anionic surfactants such as polyacrylic acid, hydrolyzed polymethylene, etc.

Benzalkonium chloride used in detergent

Used for disinfection of medical equipment, also used for sanitation and washing in swimming pools, laundry rooms, and public places, and cleaning of food industry equipment

Benzalkonium chloride can be used in the textile printing and dyeing industry as a bactericidal and mildew-proofing agent, softener, antistatic agent, emulsifier, conditioner, etc.

Benzalkonium chloride used in wet wipes

sanitary wipes are the most important difference between sanitary wipes and general wet wipes, because sanitary wipes mainly rely on these active ingredients for sterilization. In order to achieve an effective antibacterial effect, some effective bactericidal ingredients must be added, such as benzalkonium chloride, benzalkonium bromide, chlorhexidine gluconate, chlorhexidine acetate, etc. with bactericidal effect. Benzalkonium chloride wipes should avoid contact with eyes or mouth during use to prevent side effects. When skin allergy occurs during use, it should be stopped in time to avoid serious consequences.

Benzalkonium chloride can also be widely used in personal care products,

such as hand sanitizer, toilet paper, body lotion, deodorant, shampoo, conditioner and cosmetics, etc. It has good antistatic, soft effect.

benzalkonium chloride used in Oil & gas industry as strong biocide , to prevent pipe from being blocked and rusted.

Benzalkonium chloride used in Applications in plantation and animal farming :

Use 2-5% benzalkonium chloride (1227) solution to spray and disinfect grain warehouses, livestock pens, jamsils, and the breeding places and appliances of cash crops such as mushrooms and white fungus.

Benzalkonium chloride is also used as a preservative for paste, gelatin and photographic film