It is not unusual to have a problem with your mouth from time to time. A mouth problem can involve your gums, lips, tongue, inner cheeks, the roof of your mouth (soft and hard palates), under your tongue, your neck, or your teeth. Your mouth may be dry, or food may not taste right. You may have bad breath or a sore on your lip, gums, or tongue that makes it hard to eat or talk. Many of these problems can get better with home treatment.

Common mouth problems include:

• Sores, such as cold sores (also called fever blisters), canker sores, and impetigo. Canker sores develop inside the mouth, while cold sores and impetigo usually affect the area around the outside of the mouth.
• Infections, which can be caused by a virus (such as herpes simplex) or a bacteria (such as epiglottitis or a sexually transmitted disease). An infection is more serious when it causes rapid swelling of the tongue or throat and blockage of the airway.
• Tender, red splits or cracks at the corner of your mouth (angular cheilitis), which can be caused by infection, a diet too low in vitamins, and over-closure of the mouth in someone who has been without teeth or dentures for some time.
• Chapped lips, which may be caused by dry, windy, cold, or very hot weather.
• Dry mouth (xerostomia), which may be caused by dehydration, breathing through your nose, anxiety, and many medicines. Over time, having a dry mouth increases your risk of mouth infections, gum disease, and dental cavities.
• Thick, hard white patches inside the mouth that cannot be wiped off (leukoplakia). This is commonly caused by irritation of the mouth, such as from a rough tooth or poorly fitting denture rubbing against tissue or from smoking or using smokeless (spit) tobacco.
• Thrush , a common infection of the mouth and tongue caused by the yeast Candida albicans. Thrush appears on the mouth and tongue as white patches that look like cottage cheese or milk curds. When the patches are wiped away, the underlying area appears red and raw and may bleed. In babies, thrush may cause a rash in the diaper area.
• Taste changes. Your sense of taste may be decreased, lost, or changed, such as a metallic taste in your mouth.

Your tongue may become sore or swollen, or it may change color or texture. A buildup of food and bacteria on the tongue may make the tongue look thick or furry ("hairy tongue"). Often the problems will go away if the surface of the tongue is regularly brushed with a soft-bristled toothbrush. If your tongue problem is from some local irritation, such as tobacco use, removing the source of the irritation may clear up the tongue problem. Rapid swelling of the tongue can be caused by an allergic reaction, which can interfere with breathing. For more information, see the topic Allergic Reaction.