Why does a bitter taste in the mouth cause bad breath?

1. Physiological factors: These include improper diet, such as long-term consumption of spicy and irritating foods, as well as pungent foods like scallions and garlic; staying up late regularly, which reduces saliva secretion in the mouth and increases anaerobic bacteria; and inadequate oral hygiene, allowing bacteria to break down food residues and produce bad odors. 2. Pathological factors: Oral diseases such as periodontitis and gingivitis can promote bacterial growth and produce foul odors. Gastrointestinal disorders, including peptic ulcers and chronic gastritis, may cause abnormal gastrointestinal motility leading to halitosis. Additionally, chronic constipation can prevent timely elimination of harmful substances from the body, allowing them to be absorbed into the bloodstream and contribute to bad breath. 3. Other factors: Certain medications, such as sedatives and antihypertensive drugs that reduce saliva production, may also cause halitosis. Eating a heavy dinner, especially one high in greasy or spicy foods, can similarly lead to bad breath. Preventing and treating halitosis requires comprehensive consideration of these factors and the implementation of appropriate measures.