There are many reasons for excess saliva in the mouth, such as physiologic factors, oral diseases, stomach diseases, salivary gland diseases, etc. 1. Physiological factors: Eating too acidic food can lead to the phenomenon of excessive saliva in the mouth. Secondly, children during teething will also have more saliva in their mouths, which is a conditioned reflex and is normal. 2. Oral diseases: periodontitis, dental caries, stomatitis and other diseases, there will also be more saliva in the mouth. 3. Gastric diseases: gastric ulcer, gastritis, reflux esophagitis, etc., can lead to the phenomenon of acid reflux in the mouth, which will lead to more saliva in the mouth. 4. Salivary gland diseases: Salivary fistula can also lead to the phenomenon of saliva in the mouth, the disease will lead to increased saliva outflow, so it will cause a lot of saliva in the mouth. There are many reasons for more saliva in the mouth, if you exclude physiological factors, it is recommended to go to the hospital as soon as possible, follow the doctor’s instructions to take standardized treatment, not private treatment, so as not to lead to adverse consequences.