A method for treating canker sores with oral patches to speed healing and relieve pain. If certain medications are applied to a canker sore using an oral patch that restricts local flow of saliva and delivers the medication for at least 30 minutes and the patches are used for at least two or more hours per day, the method reduces the healing time for canker sores from typical 10 - 14 days to 2 days. The method can be used with various antimicrobials that speed the healing of canker sores, including penicillin and amoxicillin. The method can also be used with amlexanox and de-glycyrrhizinated licorice extract (DGL) which work by an unknown method. When used with DGL, the method also quickly relives canker sore pain and, if used before commencing a meal, typically relieves pain through a complete meal. A soluble oral patch with DGL is disclosed.