Mouthwash is an over-the-counter or prescription liquid that patients usually swish in their mouth and then spit out. There are many different types of mouthwashes that claim to serve different functions.

Mouthwashes are usually classified into one of two categories:

• Cosmetic mouthwashes. Most over-the-counter commercial mouthwashes fall into this category. In most cases, they are designed to mask bad breath (halitosis), rinse debris from the teeth and gums and temporarily reduce the amount of bacteria in the mouth.
  
  
• Therapeutic mouthwashes. These offer the same benefits as cosmetic rinses, but also help prevent or treat certain oral health conditions, such as the build-up of dental plaque. This includes prescription antiplaque and antigingivitis rinses, as well as rinses that contain fluoride (which strengthens the teeth and protects them from decay). Some may also provide relief from oral pain.

Cosmetic mouthwashes have a limited effect on dental health. Although manufacturers tout over-the-counter mouthwashes as an effective way to promote oral health, dental experts generally do not believe that they offer significant benefits over simple flossing and brushing with a toothpaste containing fluoride. In addition, cosmetic mouthwash masks, rather than eliminates, bad breath. Its effects are temporary and usually do not last more than three hours.

Patients should consult their dentist about whether they should use a mouthwash and what type may be most appropriate for them. A dentist may recommend or prescribe certain types of mouthwashes for patients at high risk of tooth decay, periodontal (gum) disease and dry mouth (xerostomia). In addition, the use of mouthwash may be recommended following oral surgery or periodontal treatment.

While mouthwashes are generally safe, some can cause side effects in patients who use them. For example, many over-the-counter mouthwashes contain high levels of alcohol that may range from 18 percent to 26 percent. Overuse of these rinses can create a burning sensation in the cheeks, teeth and gums. Additional side effects may appear as the result of use of certain types of prescription-strength mouthwashes.

Mouthwashes are generally not recommended for use in children 12 and younger. There is the risk that children may swallow mouthwash instead of spitting it out. This can lead to alcohol poisoning or fluoride overdose, which require emergency medical attention.