Poor dental hygiene

Bacteria breaks down food particles trapped in the teeth or mouth. The combination of the bacteria and decaying food in your mouth produces an unpleasant odour. Brushing and flossing regularly removes trapped food before it decays.

Brushing also removes plaque, a sticky substance that builds up on your teeth and causes odour. Plaque build-up can cause cavities and periodontal disease. Bad breath also can be a problem if you wear dentures and don’t take them out and clean them every night.

Strong foods and beverages

When you eat onions, garlic, or other foods with strong odours, your stomach absorbs oils from the foods during digestion . These oils pass into your bloodstream and travel to your lungs .

This produces an odour that others can notice in your breath for up to 72 hours. Drinking beverages with strong odours, such as coffee, can also contribute to bad breath.

Sinus, mouth, or throat conditions

 Bad breath odour may develop if you have:

• A sinus infection
• postnasal drainage
• chronic bronchitis
• an infection in your upper or lower respiratory system
• Tonsil stones, which tend to collect bacteria, can also be a source of bad breath.

Smoking

Smoking cigarettes or cigars causes a bad odour and dries out your mouth, which can make your breath odour even worse.

Dry mouth

Dry mouth can also occur if you don’t create enough saliva. Saliva helps keep your mouth clean and reduces odour.

Dry mouth can be a problem if you have a salivary gland condition, sleep with your mouth open, or take certain medications, including those that treat high blood pressure and urinary conditions.

Periodontal disease

Periodontal disease, or gum disease, happens when you don’t remove plaque promptly from teeth. Over time, plaque hardens into tartar. You can’t remove tartar by brushing, and trying to do so further irritate your gums.

Tartar Plaque may cause pockets, or small openings, to form in the area between the teeth and gums. Food, bacteria, and further dental plaque can collect in the pockets, causing a strong odour and worsening the gum disease .

Diseases

Unusual breath odour can be a symptom of some diseases. These include:

• kidney disease or failure
• liver disease or failure
• diabetes
• sleep apnoea
• gastroesophageal reflux disorder (GERD), which is a relatively common cause of halitosis