Can using hydrogen peroxide as mouthwash be harmful?

Possibly: Hydrogen peroxide (h2o2) does very little to benefit the oral health or healing. Some investigators question its use due to the fact that peroxides are free radicals and those have been linked to cancer.

Excellent stuff: Hydrogen peroxide is an excellent mouthwash. It will keep your gums healthy. Overuse can cause a change in the types of bacteria that grow in the oral cavity.

Manual Brush +: Remember that mouthwash does not take the place of proper teeth cleaning: 1) use a soft manual toothbrush. 2) place the brush where the teeth and the gum join together. 3) move the brush in circles. 4) do all teeth this way on the face side and the tongue side. 5) follow up with a water pik spraying water in circles same places.