Benzalkonium chloride: Uses, risks and safe choices

Benzalkonium chloride (BAC) is a common preservative and antiseptic you'll find in eye drops, nasal sprays, hand sanitizers, and surface disinfectants. Manufacturers like multi-dose eye drop makers add BAC to stop bacteria from growing after opening. It works fast and keeps products stable, which is why it shows up in many over-the-counter items.

How it affects you depends on where and how long you use it. Short-term use on skin or surfaces is generally fine for most people. But in the eye, even small amounts can irritate the surface with repeated use. People who use preserved eye drops day after day—those with chronic dry eye or glaucoma—sometimes notice redness, burning, or worse tear film problems. Contact lens wearers can also react to BAC because it sticks to lens material and increases irritation.

If you have sensitive eyes, you have practical choices. Look for "preservative-free" eye drops or single-use vials that use no BAC. Some brands use gentler preservatives like polyquaternium-1 or sodium perborate which break down in the eye and cause less irritation. Talk to your eye doctor about switching if your eyes feel worse after using certain drops.

On skin and surfaces, BAC is effective against many bacteria and some viruses. It's widely used in healthcare for wiping equipment or cleaning small areas. For routine hand hygiene, alcohol-based sanitizers tend to work faster against a wider range of germs, but products with BAC can help when alcohol isn’t an option. If you have broken skin or allergies, avoid repeated use and check with a pharmacist.

Safety tips that actually help:

Read labels. BAC will be listed in the ingredients for preserved products.

For chronic eye conditions, favor preservative-free formulations or single-dose vials.

Avoid mixing disinfectants—some combinations reduce effectiveness or make harmful fumes.

If you get persistent irritation, stop use and see a healthcare provider.

Store multi-dose bottles as instructed and discard after the recommended time.

Alternatives and when they make sense vary by product. For eye care, preservative-free or newer mild preservatives are worth trying. For surface disinfection, simple soap and water often do the job for routine cleaning, while hospital-grade disinfectants should be used when higher risk is present. For hand hygiene, alcohol-based sanitizers remain the first choice for quick, broad protection.

If you’re researching products here on ADW Diabetes Pharmaceutical Centre, check our articles on eye care, nasal sprays, and disinfectant choices. We focus on practical tips for people managing chronic conditions who need safe, reliable products. Have questions about a label or a specific medicine? Reach out to your pharmacist or our contact page for tailored advice.

When to talk to your doctor

See your doctor if you have ongoing eye redness, vision changes, or pain after using products that list BAC. Also speak up if skin reactions won't clear or if you need long-term nasal sprays. Your provider can suggest preservative-free options, alternative antiseptics, or testing for allergies.

Quick checklist

Label, duration, symptoms, and preservative-free options. Ask pharmacist.