• Dental infections: Tooth cavities, Periodontal {gum} disease, surgical wounds, and dying teeth are all causes of bad breath
  • Food: As food particles break down in the mouth, bacteria increase, resulting in bad odours. Onions, garlic, and certain spices are common bad-breath causes.
  • Tobacco products: Smoking tobacco also results in a smelly breath, as does chewing tobacco.
  • Dental habits: Not brushing your teeth regularly is a common cause of bad breath. This happens when tiny bits of food stay trapped in your mouth. Your tongue can be another bad-breath cause as bacteria coats it, causing foul odours.
  • Dry mouth: A condition called dry mouth, to be a bad-breath cause as saliva in the mouth is reduced. Dry mouth is a common cause of morning breath, especially in people who sleep with their mouth open.
  • Postnasal drip: Mucus that hardens in the tonsils can be a cause of bad breath. Chronic postnasal drip and sinus drainage are also bad-breath causes
  • GERD: An acidic stomach or chronic reflux of stomach acid (gastroesophageal reflux disease, or GERD) is linked to bad breath. Treating GERD may cure the bad breath.
  • Other causes: Some types of cancer and metabolic diseases can leave a distinctive breath smell. 

Talk to your periodontist if you detect metallic or other odours. it's difficult to assess how your own breath smells, ask a friend or relative to confirm your bad-breath.

While poor dental hygiene accounts for most cases of halitosis, bad breath can sometimes signal another underlying medical condition.