Bad breath (halitosis)

Bad breath (halitosis)
International Classification (ICD) R19.6



Exhaled air is normally odorless. If you can still smell it, it is bad breath.

This can occur either for a short time, after eating foods such as onions and garlic, or in the long term and thus become a nuisance.

The cause is usually hidden in the oral cavity. Inflammations, inadequate care of teeth and gums, but also lung or stomach diseases can result in bad breath.


Many different diseases can cause bad breath. Mostly, however, the reason is found in the mouth, nose, throat or sinuses.

Exhaled air can be smelled, for example, by bacteria that decompose food residues and release sulphurous and other gases. Protein-containing foods, e.g. dairy products and fish, promote bad breath.

Poor dental hygiene and cleaning of dentures

  • Caries (hole in the tooth)
  • Gingivitis (inflammation of the gums)
  • Periodontitis (infection of the periodontium)
  • Tooth root inflammation
  • Food residues in interdental spaces

Oral cavity

  • Dry oral mucosa due to sleeping with the mouth open, chronic mouth breathing, snoring, certain medications, general disease
  • Tongue coating due to eating too quickly (the tongue is cleaned when chewing), poor oral hygiene
  • Purulent inflammations in the area of the oral mucosa, teeth and after tooth extractions

Throat (pharynx)

  • Throat inflammation
  • Fissured palatine tonsils, which retain food and cell debris
  • Chronic tonsillitis (with white vesicles)
  • Chronic inflammation of the mucous membranes, catarrh of the throat
  • Rare malignant tumours


  • Chronic nostril inflammation
  • Sinusitis
  • Smoking
  • Chronic bronchitis
  • Pneumonia (lung inflammation)

Esophagus, stomach

  • Chronic gastritis (acid regurgitation)
  • Changes in the oesophagus (diverticula, very rare)

General diseases

  • Diabetes mellitus with poor adjustment (acetone odor)
  • Liver and kidney dysfunction (ammonia smell)
  • Prolonged fasting (acetone odour)


Bad breath is manifested by bad smelling breath. Often this is not noticed by the affected person, but by those around them.

Bad breath that lasts a few hours comes from certain foods such as onion or garlic. This can be easily alleviated with increased oral hygiene.

Pathological bad breath, on the other hand, is a permanent burden (halitosis, foetor ex ore).

Bacteria that proliferate in the mouth and throat also release more sulphurous gases and fatty acids when decomposing food residues. This leads to a pronounced foul odor.

Sometimes the cause can be attributed to the smell. Acidic bad breath, for example, is characteristic of a disease of the stomach, while acetone odor is characteristic of prolonged fasting and poorly controlled diabetes.

Bad breath is also typical for smokers.


It is important to find out what is causing the bad breath. This may require examinations by various specialists.

  • Dentist: examination of fillings, crowns and gums.
  • ENT doctor: examination of nose and sinuses, throat
  • Internal medicine specialist (internist): detection or exclusion of gastrointestinal diseases
  • FA for pulmonary medicine: examination of respiratory tract and lungs


The therapy depends on the cause.

Defective fillings should be treated by a dentist.

If the cause is not in the oral cavity, the appropriate specialist must determine the treatment.


It also depends on the cause. If bad breath is caused by certain foods, the condition improves after the food in question is avoided.

Oral hygiene helps with causes such as dental and tongue plaque. Here, flossing should not be forgotten to clean the spaces in between as well. Other aids like tongue cleaners and antibacterial mouthwashes are also a recommended addition.

A dentist will explain how daily oral hygiene should be carried out, what all this involves and whether professional cleaning may be necessary.

If bad breath is caused by diseases, a visit to the doctor and adequate treatment are essential to improve the breath.


If no disease is responsible for bad breath, you can easily prevent it with improved oral and dental hygiene:

  • Use dental floss or interdental brush 1x daily.
  • If possible, brush your teeth after every meal (wait 30 minutes!), but at least twice a day.
  • Use a tongue cleaner regularly
  • Regular dental check-ups
  • Have tartar and stubborn plaque removed by the dentist
  • Eat plenty of fresh fruit and vegetables
  • Drink plenty of fluids
  • Rinsing with plaque-reducing agents (consult your dentist!)
  • Chlorophyll tablets
  • Chewing gum and pastilles



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