What Causes Bad Breath? You Need to Know Before You Can Cure It!

This list comes from the National Institutes of Health:

Common Causes for Bad Breath

If previously normal breath turns into halitosis, causes could include:

Food or beverages consumed (such as cabbage, garlic, raw onions, or coffee)
Vitamin supplements (especially in large doses)
Poor dental hygiene
Dentures
Cavities
Tobacco smoking
Alcoholism
Throat infection
Sinusitis
Lung infection
Gum disease (gingivitis, gingivostomatitis)
Abscessed tooth
Impacted tooth
Foreign body in the nose (usually in children)
Often (but not always) there is a white, yellowish, or bloody discharge from one nostril

Drugs
Paraldehyde
Triamterene and inhaled anesthetics
Insulin - injection

Diseases that may be associated with breath odor (not presented in order of likelihood -- some are extremely unlikely):
Acute necrotizing ulcerative gingivitis
Acute necrotizing ulcerative mucositis
Acute renal failure
Bowel obstruction (can cause breath to smell like feces)
Bronchiectasis
Chronic renal failure (can cause breath to smell like ammonia)
Diabetes (fruity or sweet chemical smell with ketoacidosis)
Esophageal cancer
Gastric carcinoma
Gastrojejunocolic fistula (fruity-smelling breath)
Hepatic encephalopathy
Diabetic ketoacidosis
Lung abscess
Ozena, or atrophic rhinitis
Periodontal disease
Pharyngitis
Zenker's diverticulum

Click here to learn how to cure your bad breath.