Bad Morning Breath – Causes

Bad breath in the morning is not unusual and can vary from a stale odor to a slightly smelly breath. However in some cases the odor may be so offensive that the breath may resemble the smell of feces, flatus, fish or even rotting or decaying organic matter (similar to a garbage can or dead animal). Despite good oral hygiene before bedtime and a clean bill of health from a dentist, the bad morning breath may persist.

A person with chronic bad breath (halitosis) is likely to have an offensive morning breath but at times, bad morning breath exists almost exclusively with no indication of halitosis during the day. The cause of bad breath may be due to oral, pulmonary (respiratory passages) or gastrointestinal (gut) disorders.

Cause of Morning Breath

Whether you refer to it by endearing terms like¬† ‘kitty breath’, ‘puppy breath’ or just ‘morning mouth stink’, the morning breath has an odor that is between neutral and unpleasant although sometimes it is offensive. The odor of the common morning breath is due to a combination of factors.

  1. Oral bacteria. There is a diversity of bacteria living within the mouth, feeding off food particles trapped between the mouth structures (like gum and cheek)  or between the teeth. These bacteria produce gas as a byproduct and cause the trapped food to release an offensive odor due to decomposition.
  2. Dry mouth. Saliva production reduces during sleep and this allows oral (mouth) bacteria to multiply. For the reason above, the gas production both from bacterial consumption as well as the odor from decomposing food intensifies.
  3. Enclosed space. In most cases the mouth remains closed for most of the time while asleep. Oral bacteria can never be entirely eradicated despite the most meticulous hygiene and the bacterial gas production within an enclosed space intensifies the odor.

Causes of Bad Breath in the Morning

Bad breath in the morning may be due to similar causes of halitosis. If good oral hygiene is practiced before sleep yet an offensive or putrid odor is present upon waking, then further medical investigation is warranted.

Some of the causes of bad breath in the morning include :

  • Gum and tooth diseases including gingivitis, dental cavities and abscess.
  • Dental procedures like bridges, crowns and implants can contribute to halitosis if improperly inserted. Gaps between the gum, teeth and dental restoration prosthesis may trap food and be difficult to reach with conventional cleaning methods.
  • Diabetes.
  • Infection (bacteria or fungal like oral thrush) or abscess formation in the nose, nasal sinus, throat, tonsils, lungs or esophagus.
  • Necrotic cancer of the nose, throat, mouth, lungs or esophagus.
  • Gastrointestinal causes including gastroesophageal reflux disease (GERD), H.pylori infection of the stomach, small intestinal bacterial overgrowth (SIBO), Zencker’s diverticulum, gastroparesis and extreme dieting especially with ‘starvation diets’.
  • Chronic drugs – pharmaceuticals.
  • Alcohol abuse.

Please note that any information or feedback on this website is not intended to replace a consultation with a health care professional and will not constitute a medical diagnosis. By using this website and the comment service you agree to abide by the comment terms and conditions as outlined on this page