Hydrogen Peroxide for Canker Sore
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Hydrogen Peroxide for Canker SoreCanker sores, also known as mouth ulcers or aphthous ulcers, are sores with yellow or white-gray centers and bright red borders. They are caused by everything from poor diet and stress to vitamin deficiencies, mouth trauma, and a weak immune system. They occur in and around the mouth, in the throat, on the inner cheek, and on the tongue, and are not to be confused with cold sores, which occur on the outer edges of the mouth.

While not contagious, canker sores are painful and embarrassing. But you’re about to discover how to cure them safely, quickly, and naturally. Commonly used as an antiseptic or bleaching agent, Hydrogen peroxide (H2O2) is one of the most effective cures for canker sores. Let’s take a look at how it works.

How Hydrogen Peroxide Cures Canker Sores

  • Hydrogen peroxide is antibacterial and antiseptic. It kills the bacteria in and around the mouth, healing canker sores and reducing inflammation.
  • Hydrogen peroxide will produce noticeable results within 24 hours, and as it begins to work, it relieves the pain of canker sores.
  • Using hydrogen peroxide as a mouth wash on a regular basis will help maintain healthy levels of bacteria and prevent future canker sores.

How to Use Hydrogen Peroxide to Cure Canker Sores

The popular methods listed below will relieve the pain and discomfort of canker sores and speed up the healing process. Try each one until you find the one that works best for you.

1. Hydrogen Peroxide with Water

  • Mix equal quantities hydrogen peroxide and water.
  • Use the solution to rinse your mouth, swishing for 1-2 minutes, then spitting it out.
  • Or use a cotton ball to apply it directly to the sore.
  • Do not swallow the solution.
  • Do not eat or drink for an hour after treatment.
  • Repeat regularly to prevent future canker sores.

2. Hydrogen Peroxide with Salt and Baking Soda

  • Mix small amounts of hydrogen peroxide, salt, and baking soda.
  • Rinse your mouth with it 4-5 times a day.
  • Repeat regularly to prevent future sores.
  • Note: Baking soda neutralizes acidity in order to soothe the pain of a canker sore.

3. Hydrogen Peroxide with Milk of Magnesia

  • Rinse mouth with mouthwash or saltwater.
  • Mix equal parts hydrogen peroxide and water.
  • Use a cotton ball to apply the solution to the canker sore.
  • Leave on a few minutes, then dab milk of magnesia over it.
  • Leave it fir few minutes, then mix equal parts milk of magnesia and liquid Benadryl.
  • Rinse your mouth with it, swishing for 1-2 minutes, then spit.
  • Repeat 3-4 times a day.

4. Plain Hydrogen Peroxide

  • Use a cotton ball to apply plain hydrogen peroxide to the canker sore.
  • Or swish a capful in your mouth for 10 minutes, wait 10-15 minutes, and rinse with water.
  • Repeat once a day for 2-3 days.

5. Gargle with Hydrogen Peroxide and Zinc Lozenges

  • Mix equal parts hydrogen peroxide and water.
  • Dissolve 1-2 zinc lozenges in the solution.
  • Gargle with it, then spit it out. Do not swallow.
  • Repeat 3-4 times daily until you see results.

Tips & Precautions

Keep the following pointers in mind in order to avoid side effects while using hydrogen peroxide.

  • Swallowing hydrogen peroxide will cause an upset stomach.
  • To prevent the hydrogen peroxide from killing the good bacteria in your mouth and causing dental problems, use it only as often as your preferred method recommends.
  • In addition to using the above methods to cure and prevent canker sores, eat a balanced diet that provides your body with the vitamins, minerals, proteins, and probiotics it needs to keep you healthy.

Have you tried any of these methods to cure a canker sore? Do you know of other methods we haven’t mentioned? Share your experience with us!


  1. By using plain hydrogen peroxide by inner cheeks are also effected, like it is paining alot, it has been one day but the pain has not gone, I want to ask is this because of using hydrogen peroxide? I’m not gonna use that again.

    1. It usually depends on the severity of your canker sore. Healing will cause some pain, it’s common for all, however we recommend to dilute it with water or milk of magnesia as mentioned in the article.

      1. I get these ulcers in my mouth tongue throat and balls. I dont know if any of these could help my throat ones cause I can’t swallow it and do you know if it can help the balls on. Btw I have never had sex with anyone or anything so the isnt genital herpies.

  2. 50% hydrogen peroxide and 50% water works temporarily for pain. I have the white ulcers in the back of my mouth / tongue and down my throat. I can hardly eat or drink anything, or sleep! The pain is quite severe. Gargle twice for about 1 minute each.
    For people who get them routinely in the front of their mouth on lips or gums, I suggest Vitamin B-Complex pills, or food high with this, before, during, and after an outbreak, as a deficiency is known to trigger these sores in some people.

    1. Yes, you can use. You can try 1 or 2 method mentioned in the above article. Apart from that include vitamin B rich foods in your diet.

  3. Peroxide has helped me get rid of canker sores in my mouth. I never have pain with the canker sores. Also an aspirin put right on it also helps. Peroxide and water, swish around your mouth

  4. I use hydrogen peroxide rinse for mouth ulcers and the strongest Oragel for toothaches to paste over at
    night in order sleep. also include B12 daily supplement.

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