What are Canker Sores ?

Canker sores, also known as aphthous ulcers, are small sores that occur inside the mouth. You can get them on the tongue and on the inside of the cheeks and lips - the parts of the mouth that can move. They usually pop up alone, but sometimes they show up in small clusters.

Canker sores are shallow, painful sores in your mouth. They are usually red or may sometimes have a white coating over them. You might get them on the inside of your lips, the insides of your cheeks, the base of your gums or under your tongue. Canker sores are different from fever blisters, which usually are on the outside of your lips or the corners of your mouth.

Your mouth might tingle or burn before the actual sore appears. Soon, a small red bump rises. Then after a day or so it bursts, leaving an open, shallow white or yellowish wound with a red border. The sores are often painful and can be up to an inch across, although most of them are much smaller. Occasionally, someone who gets canker sores may also develop a fever and feel sluggish and uncomfortable.