How long will it take a canker sore to heal?

Depending on their severity, canker sores heal in one to six weeks. Minor ones may heal in one to three weeks, while major sores may take up to six weeks. With a canker sore, pain is often only felt for a week to 10 days.

Usually, the sores heal by themselves without needing any medical intervention. Home remedies include eating soft foods, drinking lots of fluids, rinsing one's mouth with salt water and applying an over-the-counter cream containing a cortical steroid. If the sores remain symptomatic or do not seem to be healing after two weeks of using home remedies, a doctor may need to prescribe treatment.