
Why is the breath from my mouth so foul-smelling?
Recently, when I was talking to my father, I noticed that the breath he exhaled from his mouth smelled like feces; may I ask what could be the cause of this?

Oral malodor, known as halitosis, is mainly caused by the following factors:
1. Physiological factors: Consuming large amounts of pungent foods such as Chinese chives and garlic, or long-term intake of spicy and fishy-smelling foods like onions and ginger, can lead to bad breath. In addition, smoking and alcohol consumption are also common causes of halitosis.
2. Poor oral hygiene: Food residues and bacteria accumulating in areas such as between the teeth and on the tongue may decompose and produce sulfide compounds, which are the most common cause of bad breath.
3. Oral diseases: Conditions such as gingivitis, periodontitis, and dental caries can cause food residues and bacteria to accumulate in the periodontal pockets, resulting in a foul odor.
4. Dry mouth: Saliva helps clean the oral cavity. When the mouth is dry, reduced saliva production allows bacteria to multiply easily, leading to halitosis.
5. Digestive system diseases: Conditions such as gastritis, gastric ulcer, and Helicobacter pylori infection can cause gastroesophageal reflux during indigestion, which may also result in bad breath.
If symptoms persist or worsen, timely medical consultation is recommended.