Yellow saliva can be caused by a number of factors, including bacteria or acid in the mouth. It can be a sign of other problems as well, such as infection or acid reflux. These conditions may require treatment by a doctor or dentist.
The presence of yellow saliva early in the morning may result from the buildup of bacteria on the teeth, tongue or other tissues in the mouth. This often results in halitosis, or bad breath, and can increase the likelihood of tooth decay. Bacteria in the mouth can usually be controlled by good oral hygiene practices, such as brushing and flossing regularly. Brushing or scraping the tongue is especially important for halitosis sufferers. If these measures are not sufficient, a dentist may be able to provide other suggestions for getting rid of the bacteria that cause halitosis and yellow saliva.
If accompanied by a runny nose, cough or other cold symptoms, yellow saliva may be due to an excess of yellow mucus. Mucus is usually clear and present only in small amounts of the saliva. A cold, sinus infection or other respiratory illness, however, often causes mucus to turn yellow or green. Either viral or bacterial illnesses can result in yellow mucus. Some of these conditions clear up on their own, but if abnormal saliva and mucus remain for more than a few days or are accompanied by severe discomfort, the patient should seek advice from a medical professional.
Acid reflux may also cause yellow saliva, especially in the morning. This is a condition in which the digestive juices found in the stomach are regurgitated into the esophagus. When the patient is lying down, these juices may make their way into the mouth, resulting in yellow or brown saliva. If the yellow saliva is accompanied by heartburn or nausea, it is likely due to acid reflux. In addition to the discomfort of acid reflux, the presence of acid in the mouth may lead to tooth decay or other oral health problems.