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Bad Breath

Bad Breath (Halitosis) Overview

Bad breath, also called halitosis, can be an embarrassing problem. It can be caused by the foods one eats, dry mouth, tobacco products, or a medical disorder. Maintaining proper oral health can help reduce or eliminate bad breath.

Bad Breath Causes

Bad breath (halitosis) can be caused by a variety of things, including diet, medication, poor oral hygiene, and diseases or conditions such as diabetes, GERD, lactose intolerance, gum disease, and more. Treatment for bad breath depends on the cause.

Medications that cause a dry mouth can trigger bad breath. In addition, certain medications, such as triamterene and paraldehyde, have bad breath as a side effect.

Causes of bad breath include the following:


  • When a person does not brush or floss their teeth thoroughly, food particles that may remain in the mouth can rot and cause foul odors. In addition, food particles over time can promote the growth of bacteria, which can also cause foul odors. The bacteria can also lead to tooth decay and gum disease.
  • Foods with strong odors also affect the air a person exhales. Foods commonly known to contribute to bad breath include onions and garlic, exotic spices (such as curry), some cheeses, fish, and acidic beverages such as coffee. These foods may also cause stomach and gastrointestinal upset and belching, which can contribute to bad breath. In addition, certain supplements, such as fish oil capsules, can contribute to bad breath.
  • Low-carbohydrate diets may also cause what is known as "ketone breath." So-called "low carb" diets cause the body to burn fat as its energy source. The end product of making this energy is ketones, which cause a fruity acetone-like odor on the breath when exhaled.

Dry Mouth

  • Bad breath can also be caused by decreased flow of saliva, which is a vital part of the digestive process and removes odor-causing particles in the mouth. Also called xerostomia, dry mouth may be caused by medications, breathing through the mouth, or salivary gland problems.

Tobacco Products

  • In addition to causing bad breath, smoking or chewing tobacco-based products can stain teeth, irritate gum tissue, and exacerbate tooth decay.

Medical Disorders

The following medical disorders may cause bad breath:

Dentures or Dental Appliances

  • Dentures or dental appliances, such as braces, can contribute to bad breath. Most often, it is due to food particles that are not properly cleansed from the appliances. Loose-fitting dentures can contribute to sores and localized infections in the mouth, which can cause bad breath.

Morning Breath

  • Overnight, bacteria accumulate in the mouth, which can cause bad breath, commonly referred to as "morning breath." Some people breathe through their mouths at night, which can cause dry mouth and worsen morning breath.
Medically Reviewed by a Doctor on 7/24/2015

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