what to do for a canker sore
At-home treatment for minor canker sores include: 1  Saltwater Solution and Sodium Bicarbonate - Mix 1 teaspoon salt with one cup warm water. Swish the solution in your mouth for 30 seconds, then spit the solution out. 2  Hydrogen Peroxide Solution - Mix one part hydrogen peroxide with one part water. Use a cotton swab to dab the solution directly onto the canker sores. Do not swallow the solution. Hydrogen peroxide is an antiseptic that will help reduce a number of bacteria in the mouth.