Hydrogen Peroxide on Wounds: Uses and When to Avoid It
Medically Reviewed by Dr. Pedro Yelamo Vera, MD
Licensed Physician No. 484814280 · Official Medical College of Bizkaia (Spain)Last reviewed: 5 November 2026
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Hydrogen peroxide sold in Spanish pharmacies is a 3% solution, also called 10 volumes. As a medicine it is used to clean small, shallow skin wounds and, diluted, as a mouth rinse after a tooth is pulled. It is not for deep wounds and must not be swallowed. For a small cut, tap water is usually enough. In Spain it is called agua oxigenada. This guide is by Dr. Pedro Yelamo Vera, a GP licensed in Spain (Colegiado No. 484814280).
- Pharmacy hydrogen peroxide (agua oxigenada) is a 3% solution, also called 10 volumes.
- Its approved uses are shallow skin wounds and a mouth rinse after a tooth is pulled, from age 12.
- Do not use it in deep wounds, closed body spaces, the eyes or gum wounds, and never swallow it.
- Running tap water is enough to clean a small cut. Hydrogen peroxide can irritate the wound.
- Strong solutions for cleaning or hair are not for skin and are dangerous if swallowed.
What is hydrogen peroxide used for?
The product information for the 3% solution approved in Spain lists two uses:
- cleaning shallow skin wounds, such as scratches and grazes;
- a mouth rinse after a tooth is pulled, in adults and children over 12, always diluted with water as the leaflet says.
It fizzes on a wound because it releases oxygen. The fizzing helps lift dirt. It does not mean the wound is infected.
Should I put hydrogen peroxide on a cut?
For a small, clean cut you do not need it. Mayo Clinic and the NHS advise rinsing the wound under running water, washing the skin around it with soap and water, and covering it with a plaster. Mayo Clinic says not to use hydrogen peroxide on cuts, as it can irritate the wound. If you want an antiseptic, ask the pharmacist which one suits you.
When should you not use hydrogen peroxide?
- On deep wounds, surgical wounds or wounds that bleed a lot.
- In closed spaces of the body. Gas bubbles in the blood (gas embolism) have been reported, sometimes serious.
- In the eyes. If it splashes, rinse with plenty of water and get help if it still hurts.
- As a rinse for gum wounds.
- If you are allergic to it.
- In the ears, unless a doctor tells you to. This is not an approved use.
Do not swallow it. Do not mix it with other products, such as iodine or bleach.
Can you use hydrogen peroxide in your mouth?
Only after a tooth is pulled, diluted with water as the leaflet says. It is not for children under 12. Teens aged 12 to 18 should use it with an adult watching. It is not used for gum wounds. Rinsing often can irritate the mouth and cause "hairy tongue", a change to the tongue that goes away. Toothache or swollen gums need a dentist or doctor.
What do 10, 30 and 110 volumes mean?
The number of volumes shows how strong it is. The 10-volume solution (3%) is the one for skin. Stronger ones are used for hair dye or cleaning. They can burn the skin and eyes. Do not use them as an antiseptic.
What are the side effects?
The 3% solution on the skin is usually well tolerated. It may sting or irritate. Strong solutions can cause white burns on the skin. The most serious risk, though rare, is gas embolism when it is used in deep wounds or closed body spaces.
What if someone swallows hydrogen peroxide?
A sip of the 3% solution usually causes only irritation, nausea or vomiting. Do not make the person sick. Call Spain's poisons information service (Servicio de Información Toxicológica, 91 562 04 20) for advice. If a strong solution was swallowed, or there is trouble breathing, severe pain or vomiting blood, call 112.
In English: what is the equivalent?
It is the same product: hydrogen peroxide 3%, sold in the UK and the US without a prescription. In a Spanish pharmacy, ask for agua oxigenada de 10 volúmenes. If you want a different antiseptic for wounds, ask the pharmacist for an antiséptico para heridas.
When to see a doctor about a wound
- There is dirt or grit that will not wash out.
- It is a bite from a person or an animal.
- It gets red, hot, swollen, more painful, or leaks pus.
- You are not sure your tetanus jab is up to date.
- You have a fever or feel unwell.
When to go to A&E or call 112
- The bleeding is heavy, spurts, or does not stop when you press on it.
- The cut is deep or large, is on the face or palm, or has something stuck in it.
- You have lost feeling or movement near the wound.
Frequently asked questions about hydrogen peroxide
Do you need a prescription for agua oxigenada in Spain?
No. The 3% solution is sold without a prescription in Spanish pharmacies. Follow the leaflet.
Why does hydrogen peroxide fizz?
It releases oxygen when it touches blood and tissue. The fizzing does not mean the wound is infected.
Can children use hydrogen peroxide?
On shallow skin wounds, yes, with care. As a mouth rinse, only from age 12, with an adult watching until 18.
Is tap water better than hydrogen peroxide for a cut?
For a small cut, running water cleans well and does not irritate. Hydrogen peroxide is not needed in most cases.
Can a doctor check a wound by video?
Yes. A doctor can look at the wound on video, check your tetanus status and decide if home care is enough or if you need to be seen in person.
Getting a medical assessment
If you have a wound that worries you or is not healing, you can book a video consultation with Dr. Pedro Yelamo Vera, a physician registered in Spain. You can also read about urgent care visits, impetigo and mupirocin. A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.
This guide is general information. It does not replace the package leaflet or the advice of your doctor or pharmacist.
Sources
This content is written and reviewed by a licensed physician with reference to the following sources.
