How to Make Hydrogen Peroxide Mouthwash
If you want a mouthwash with fewer ingredients or your dentist recommended using hydrogen peroxide, you can make a flavored hydrogen peroxide mouthwash at home. Make sure to dilute your hydrogen peroxide since it's quite harsh. To dilute it, pour 1 cup of water into a dark, glass bottle. Add ½ cup of 3 percent hydrogen peroxide and 7 to 10 drops of essential oil, like peppermint or spearmint. Make sure your hydrogen peroxide isn't stronger than 3 percent or else you risk damaging your teeth and dental work. Close the bottle and shake it to combine the ingredients. When you're ready to use your mouthwash, shake it again, pour a capful into your mouth, and swish for 2 minutes before spitting the mouthwash out, making sure to not swallow any. Finally, rinse your mouth with fresh water.
Pour 1 cup (240 milliliters) of lukewarm water into a dark bottle. You can use a glass or plastic bottle as long as it is dark-colored; light will cause the hydrogen peroxide to degrade faster. Make sure that you are using distilled or filtered water. Add 1 cup (240 milliliters) of 3% hydrogen peroxide. Use only 3% hydrogen peroxide. Anything higher could be damaging to your oral and dental health. Close the bottle, then shake it to combine the ingredients. Store the bottle in a cool, dark place until you are ready to use it. Use the mouthwash no more than twice daily. Pour some mouthwash into a cup. Swish and gargle it in your mouth for about 30 seconds, then spit it out. Rinse your mouth afterwards with water, then discard any mouthwash left in the cup. Pour 1 cup (240 milliliters) of water into a dark, glass bottle. Use only filtered or distilled water. You can also use peppermint or spearmint hydrosol instead for a minty flavor. Avoid using plastic bottles, as the essential oils can cause the plastic to degrade over time. Add ½ cup (120 milliliters) of 3% hydrogen peroxide. It is very important that you use 3% hydrogen peroxide; anything higher could damage your teeth. Most grocery stores sell 3% hydrogen peroxide, however. Add 7 to 10 drops of essential oil. Peppermint or spearmint would work the best for mouthwash. You can try another type, such as: clove, grapefruit, lemon, rosemary, or sweet orange. Mixing 1 tablespoon (22.5 grams) of honey into the essential oil will help emulsify it. Skip this step if a child will be using the mouthwash. Close the bottle, then shake it to combine the ingredients. Keep in mind that you will need to shake the bottle each time before you use the mouthwash. Use the mouthwash. Give the mouthwash a shake, then swish and gargle a capful in your mouth for 2 minutes. Spit the mouthwash out, then rinse your mouth with water. Do not swallow the mouthwash. Store the mouthwash in a cool, dark place. 
Pour 1 cup (240 milliliters) of lukewarm water into a dark bottle. Add 1 cup (240 milliliters) of 3% hydrogen peroxide. Close the bottle, then shake it to combine the ingredients. Use the mouthwash no more than twice daily. Pour 1 cup (240 milliliters) of water into a dark, glass bottle. Add ½ cup (120 milliliters) of 3% hydrogen peroxide. Add 7 to 10 drops of essential oil. Close the bottle, then shake it to combine the ingredients. Use the mouthwash. 