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Hydrogen peroxide is a chemical that comes in varying strengths. Chances are, you have a bottle of 3 percent hydrogen peroxide in your medicine cabinet.

You may use it to disinfect minor cuts, or to gargle with. If you swallow a tiny amount, it is not likely to hurt you. Drink too much, however, and you can become sick.

Stronger hydrogen peroxide solutions can be dangerous, or even fatal, if ingested or inhaled. They can also burn your skin and eyes.

In this article, we’ll go over everything you need to know about potential dangers from this common medicine cabinet staple.

Hydrogen peroxide can be purchased as a topical solution. It is also an ingredient in commercial products such as tooth whiteners and hair dye. The percentage of hydrogen peroxide in these products vary.

Hydrogen peroxide is available in many strengths or dilutions. In general, there are four main types:

  • Household (3 percent). This type of hydrogen peroxide is commonly used as a mouthwash or gargle. It is also used to disinfect minor wounds and household surfaces.
  • Hair bleach (6 to 10 percent). As its name implies, this dilution of hydrogen peroxide is used for lightening hair.
  • Food grade (35 percent). This name is misleading. Swallowing food-grade hydrogen peroxide can make you severely ill, or cause death to occur.
  • Industrial strength (90 percent). Swallowing even tiny amounts of hydrogen peroxide at this strength can be fatal. It is toxic to drink, touch, or breathe. It should not be used for home or personal use of any kind. Industrial use hydrogen peroxide is often used to bleach fabrics, textiles, and paper products, in addition to other uses.

Hydrogen peroxide has the potential to cause injury or illness in several ways.

Ingestion

Ingestion of 3 percent hydrogen peroxide can cause:

  • vomiting
  • nausea
  • irritation of your mouth, throat, and stomach
  • gastric distension
  • foaming at your mouth, from vomiting up oxygen bubbles that have formed in your stomach
  • internal burns, although this is an uncommon symptom for this dilution

Ingestion of hydrogen peroxide at 10 to 20 percent strength can cause the same symptoms. Internal burns are more likely to occur at this strength.

Ingestion of solutions of more than 20 percent can cause the same symptoms, as well as rapid loss of consciousness and respiratory paralysis.

Gas embolism

According to Poison Control, gas embolism is a rare complication that can occur from drinking hydrogen peroxide of any strength. A gas embolism is caused by bubbles of gas or air that get into your circulatory system and block a blood vessel.

This serious complication can be fatal if not treated quickly. Symptoms of gas embolism include:

  • chest pain
  • confusion
  • difficulty breathing

Skin contact

Skin contact with household strength hydrogen peroxide is typically not dangerous. It may, however, cause minor skin irritation to occur. This kind of hydrogen peroxide may also blanch your skin. This causes your skin to whiten or lighten temporarily.

Skin contact with higher concentrations of hydrogen peroxide can cause:

  • severe irritation
  • burns
  • blisters
  • ulcers
  • scarring

Inhalation (breathing in fumes)

Breathing in household strength hydrogen peroxide can cause:

  • mild respiratory irritation
  • burning sensation in your nose, throat, or chest
  • eye irritation

Breathing in vapors from hydrogen peroxide that is more than 10 percent can cause these same symptoms, plus:

Some people drink food-grade hydrogen peroxide because they are under the false assumption that it can cure conditions such as cancer and HIV. This is unproven — and inaccurate.

In fact, a 2011 research review showed that hydrogen peroxide may slightly promote the growth or multiplication of cancerous cells. This makes it a possible cause of cancer.

It is dangerous to drink food-grade hydrogen peroxide, even if you dilute it.

Hydrogen peroxide that’s 3 percent is a common household staple used for disinfecting household surfaces, as well as minor skin wounds. It is also used as a mouthwash.

This type of hydrogen peroxide can cause minor symptoms to occur if ingested, touched, or inhaled.

More potent forms of hydrogen peroxide can be dangerous — or even fatal — to drink, breath in, or touch.

Hydrogen peroxide is not a cure for cancer, HIV, or any other disease.