DEAR DR. GOTT:
I want to know if you think a mouthwash made of one part water and one part hydrogen peroxide is good. I read about it somewhere and thought it was worth a try because it would be less costly than other rinses. Since trying it, I can’t see a problem with it. I make sure to rinse with plain water afterward so I don’t have a bad aftertaste.

Do you know if this is safe to use? Will it have adverse long-term effects?

DEAR READER:
Hydrogen peroxide is perfectly safe to use. The recipe and directions for use as a mouth wash are included on the bottle of 3% hydrogen peroxide. It recommends mixing equal amounts of water and peroxide to use as a mouth cleanser. It advises avoidance of swallowing the mixture. To the best of my knowledge the minimal amount swallowed during normal mouth cleansing will not cause harm.

You can continue to use your homemade mouthwash safely.