What causes drooling during sleep that also has a bad smell?

Drooling during sleep accompanied by a foul odor may be caused by various factors: 1. Poor oral hygiene, such as failure to brush teeth or rinse the mouth promptly, can lead to food residue remaining in the mouth, stimulating the salivary glands to secrete more saliva and producing an unpleasant odor. 2. Oral conditions such as dental malformations or periodontitis may cause incomplete closure of the teeth during sleep, resulting in drooling. Additionally, oral inflammation can contribute to bad breath. 3. Digestive disorders, intestinal parasitic infections, or gastroesophageal reflux disease (GERD) may also cause drooling with a foul smell during sleep. These conditions can lead to fermentation of food in the intestines, generating gas that is expelled through the esophagus, thereby causing halitosis. It is recommended to maintain good oral hygiene, promptly treat any oral diseases, and pay attention to dietary health to reduce the occurrence of such symptoms.