Natural treatments for sores inside the mouth include rinsing the mouth out with salt water, applying a paste of baking soda and water, or using a solution of hydrogen peroxide and water, according to MedlinePlus. Swabbing the sore with milk of magnesia is another common home solution.
Treating mouth sores with salt water is the simplest solution, requiring only a teaspoon or so of salt to a glass of water. The solution should be swished around in the mouth a few times, then spit out. Another home treatment is baking soda paste, which is prepared by adding just enough water to form a thin paste. The paste is applied directly onto the mouth sores as soon as they start to appear and repeated as often as needed. Applying a solution of equal parts water and hydrogen peroxide to the sores helps reduce bacteria and aids with the healing process. Applying a dab of milk of magnesia to the mouth sores a few times a day is another option for soothing pain, according to Mayo Clinic.
Typically, mouth sores that occur inside the mouth only are known as canker sores, according to Mayo Clinic. They appear as small, white or yellow raised ulcers on the soft tissue in the mouth. The sores can be painful, but are usually not contagious. It can take up to two weeks for the sores to fully heal, but natural treatments at home can help aid the healing process and soothe the pain.