What causes dry mouth and bad breath?

Dry mouth and bad breath may be caused by various factors, primarily including the following: 1. Oral diseases: Dental calculus, dental plaque, and food residues in the mouth create favorable conditions for bacterial growth. These bacteria break down food debris, producing unpleasant odors, and may also reduce saliva secretion, leading to dry mouth. Statistics show that 80%–90% of bad breath originates from oral problems such as dental caries and periodontitis. 2. Endocrine disorders: Certain diseases like diabetes can cause hormonal imbalances, affecting saliva production and subsequently leading to dry mouth and bad breath. 3. Poor lifestyle habits: Long-term consumption of spicy or irritating foods, insufficient water intake, and failure to rinse the mouth promptly after meals may contribute to oral dryness and bad breath. 4. Indigestion: Excessive gastrointestinal burden, delayed digestion, and accumulation and fermentation of food in the intestines may lead to bile and gastric content reflux, resulting in dry mouth and bad breath.