Health Topics A-Z

What Are the Symptoms?

• Small, painful, craterlike ulcers that appear singly or in clusters on the inside of the mouth, usually lasting 5 to 10 days. The sores are grayish white or pale yellow with red borders; they may occur on the inside of the cheeks and lips, on the tongue, at the base of the gums, or on the soft palate.
• Tingling or burning in the mouth; this sensation often occurs 6 to 24 hours before sores appear.

Call Your Doctor If:

• Your canker sores are extremely painful; your doctor can give you medication to alleviate pain.
• The sores last more than 14 days; this may indicate a more serious condition that needs treatment.
• You have persistent multiple mouth sores, which may indicate an underlying problem, such as a drug reaction or, in rare cases, oral cancer or leukemia.