Hydrogen peroxide: what to use it for, what to skip, and how to store it
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- 3% hydrogen peroxide topical solution in an opaque bottle. Best for: Household cleaning and odor removal according to the selected label. See options on Amazon
- Spray cap that fits the original peroxide bottle. Best for: Spraying counters and cutting boards without decanting. See options on Amazon
- Sterile saline wound wash spray. Best for: Rinsing cuts and scrapes in a first aid kit. See options on Amazon
- Petroleum jelly or antibiotic ointment. Best for: The step after rinsing a minor cut. See options on Amazon
- Nitrile cleaning gloves and unvented goggles. Best for: Small mold cleanups with a disinfectant. See options on Amazon
What is hydrogen peroxide?
Hydrogen peroxide is a highly reactive chemical, usually diluted in water. Its formula is H2O2: like water (H2O), but with two oxygen atoms instead of one. That extra oxygen makes it unstable, so it breaks down into water and oxygen, which is why it fizzes.
Poison Control lists the strengths you may see:
| Strength | Where it is found | Home use? |
|---|---|---|
| 3% | Household opaque bottles; separate contact-lens systems may also contain this concentration | Household cleaning as labeled; contact-lens systems need their own neutralization instructions |
| 6 to 10% | Hair bleach | Only as the product directs |
| 35% ("food grade") | Sold for alternative therapies | No. It is not food and can burn the gut if swallowed |
| Up to 90% | Industry, such as bleaching paper | No |
Should you use hydrogen peroxide on a wound?
No. Hydrogen peroxide was once used to clean skin wounds, but Poison Control says this is no longer recommended because research shows it can irritate or damage the cells needed for healing. Mayo Clinic's first aid steps for cuts and scrapes also say not to use hydrogen peroxide or iodine, since both can irritate wounds.
What Mayo Clinic advises instead:
- Wash your hands, then stop the bleeding with gentle pressure from a clean bandage or cloth.
- Rinse the wound under running water and wash around it with soap, keeping soap out of the wound.
- Remove dirt with tweezers cleaned with alcohol. See a professional if you cannot get it all out.
- Apply a thin layer of antibiotic ointment or petroleum jelly.
- Cover it with a bandage, rolled gauze, or gauze held with paper tape, and change the covering at least once a day or when it gets wet or dirty. Mayo says a very minor scrape or scratch does not need covering.
For a rinse you can carry in a kit, see our saline wound wash guide, and for covering cuts, see medical tape.
Good uses for 3% hydrogen peroxide
- Cleaning surfaces. Poison Control says it is widely used as a cleaner and disinfectant on counters and cutting boards, and to remove odors from dishwashers, sinks, garbage cans, toilets and cat boxes. It can also lift some fabric stains.
- Loosening ear wax. Poison Control describes peroxide as one liquid used to loosen wax, but that is not a reason to put a household cleaner in your ears. Ask a pharmacist or clinician about a labeled ear-care product and whether home treatment is appropriate; leave stubborn wax to a healthcare professional. Do not insert cotton swabs.
- Not for teeth. Tooth whitening products use peroxides in controlled ways. Poison Control says not to use liquid hydrogen peroxide as a substitute, and to talk to a dental professional first.
CDC's disinfection guideline describes hydrogen peroxide as active against bacteria, yeasts, fungi, viruses and spores, but results depend on strength and contact time. In one study CDC cites, a 3.0% solution did not work against VRE after 3 and 10 minutes. Follow the contact time on any product label you rely on.
Does hydrogen peroxide kill mold?
Hydrogen peroxide has fungicidal activity, but killing mold is not the main job. EPA says dead mold can still cause allergic reactions, so it must be removed, and that routine use of biocides is not recommended during mold cleanup. The key is moisture: fix the leak and dry wet areas within 24 to 48 hours.
- Scrub mold off hard surfaces with detergent and water, then dry completely.
- Porous items like ceiling tiles and carpet may have to be thrown away.
- If mold covers more than about 10 square feet, EPA points you to its professional remediation guidance.
- EPA also discusses a properly fitted N-95 respirator to limit inhaling spores. If you have health concerns, consult a clinician before cleanup; contaminated sewage, suspected HVAC involvement or substantial damage calls for professional guidance. If you do use a disinfectant, ventilate the area and wear gloves made of natural rubber, neoprene, nitrile, polyurethane or PVC, plus goggles without vent holes.
Does hydrogen peroxide expire?
Yes. Poison Control says a sealed opaque bottle should be good for about 3 years. Once opened, it starts to break down and lasts only 1 to 6 months. To check it, pour a little into a sink: if it fizzes or bubbles, it is still active.
A fizz check is not a validated test of germ-killing performance. Use the expiry and directions of the labeled disinfectant; the CDC's different results across concentrations and contact times show why bubbling alone is insufficient.
Storage and safety
- Keep it in its original opaque bottle, which protects it from light, and store it out of sight and reach of children.
- Never pour it into a cup or drink bottle. Poison Control describes a 2-year-old who drank 3% hydrogen peroxide a parent had poured into a cup to treat a cut.
- A sip of household strength may cause belching, an upset stomach, vomiting or throat irritation. A large amount, or any high-strength product, can cause burns and, rarely, a gas embolism, which is an emergency.
- For eye splashes, rinse with plenty of running water for 15 to 20 minutes. For skin, rinse with running water.
- Do not use it to make a person vomit. Use it for a pet only if your vet or a poison expert tells you to.
Contact-lens peroxide systems are separate products. FDA warns that unneutralized peroxide must never go directly into the eyes or rinse lenses immediately before insertion. Use the case supplied with each new bottle, complete the labeled neutralization time, and ask an eye-care professional before changing systems. Never substitute household peroxide for the prescribed lens-care system.
What to look for when you buy
3% hydrogen peroxide topical solution in an opaque bottle
Best for: Household cleaning and odor removal according to the selected label
Poison Control advises buying only the 3% solution for household use and keeping it in its original opaque bottle to protect it from light.
Watch out: Not for cleaning cuts, and it loses strength within 1 to 6 months of opening, so smaller bottles waste less.
See options on AmazonSpray cap that fits the original peroxide bottle
Best for: Spraying counters and cutting boards without decanting
A sprayer that screws onto the brown bottle lets you follow Poison Control's advice to keep hydrogen peroxide in its original opaque container.
Watch out: Use only a cap the product manufacturer approves; do not remove required safety closures or use a spray method the label does not permit. Keep the bottle away from children.
See options on AmazonSterile saline wound wash spray
Best for: Rinsing cuts and scrapes in a first aid kit
Mayo Clinic says to rinse wounds with water rather than hydrogen peroxide. A sealed saline spray is a clean rinse to carry when running water is not close by.
Watch out: It rinses; it does not replace seeing a professional for deep, dirty or infected wounds.
See options on AmazonPetroleum jelly or antibiotic ointment
Best for: The step after rinsing a minor cut
Mayo Clinic advises a thin layer of antibiotic ointment or petroleum jelly to keep the wound surface moist before covering it.
Watch out: Some antibiotic ointment ingredients cause a mild rash. Stop using it if a rash appears.
See options on AmazonNitrile cleaning gloves and unvented goggles
Best for: Small mold cleanups with a disinfectant
EPA recommends gloves made of nitrile or similar materials and goggles without vent holes when using disinfectants or strong cleaners on mold.
Watch out: Protection does not fix moisture or make every cleanup safe. Follow EPA guidance for areas over about 10 square feet, health concerns, sewage or suspected HVAC contamination.
See options on AmazonQuestions people ask
- What is food grade hydrogen peroxide?
- It is usually 35% hydrogen peroxide. Poison Control says that despite the name it is not food, its promoted health uses are not based on scientific evidence, and swallowing it can cause serious internal burns and death.
- What is the chemical formula for hydrogen peroxide?
- H2O2. It has two oxygen atoms where water has one, and it breaks down into water and oxygen.
- Can hydrogen peroxide expire?
- Yes. A sealed opaque bottle lasts about 3 years; an opened one lasts 1 to 6 months. If a little poured into the sink no longer fizzes, replace it. A fizz test does not prove it will disinfect a surface; follow the product's expiry and contact-time directions.
- Is hydrogen peroxide the same as rubbing alcohol?
- No. Hydrogen peroxide is H2O2, a reactive oxygen compound, while rubbing alcohol is an alcohol, most often isopropyl alcohol. They are sold for different jobs, so read each label for its uses.
- What if someone swallows hydrogen peroxide?
- For a sip of 3%, Poison Control suggests a few sips of water to clear the esophagus. Call Poison Control at 1-800-222-1222 for any swallow, and get emergency help for high-strength products or trouble breathing, chest pain or confusion.
Sources
- Is hydrogen peroxide safe? (poison.org), Poison Control, National Capital Poison Center
- Cuts and scrapes: First aid (mayoclinic.org), Mayo Clinic
- A Brief Guide to Mold, Moisture and Your Home (epa.gov), US EPA
- Chemical Disinfectants: Guideline for Disinfection and Sterilization (cdc.gov), CDC
- Hydrogen Peroxide Solution (contact-lens systems) (fda.gov), U.S. Food and Drug Administration