Saliva is made in small glands near the mouth known as salivary glands. Saliva is made of water, digestive enzymes, sodium, potassium and other chemicals. Part of the nervous system controls how much saliva is made and released. Putting food in front of a person stimulates the production of saliva. So does the smell of food. Irritating things in the mouth, such as a cold sore or braces, can also cause more saliva.
Saliva coats food and allows it to pass into the stomach without injuring the mouth or esophagus. Saliva lubricates the mouth and helps keep the mouth and teeth clean. Saliva helps people digest certain starchy foods.
Having too much saliva is called sialorrhea. You make about 6 cups of saliva each day. Most people dont notice this. But you would notice a lot more saliva than usual. You may be making more saliva or you may have more saliva in your mouth because you are not swallowing it normally.
Pregnant women often complain of too much saliva. This seems to be related to hormone changes and acid reflux. (When acid from the stomach backs up into the esophagus and mouth, the salivary glands make more saliva to protect the tissues.)
Excess saliva is also made when there is a problem in the mouth, such as an infection. People who read mystery novels know that too much saliva may be a sign of poisoning. Many poisons, including some mushrooms, arsenic and mercury, can cause too much saliva. Medications such as pilocarpine (used to treat glaucoma and other eye problems) occasionally can cause this as well.
Sometimes, people make a normal amount of saliva but have a problem swallowing it. Infections such as strep throat, a throat abscess or the mumps can make swallowing difficult. Certain neurological diseases like Parkinsons or stroke can do the same thing. People with these diseases often drool or dribble. Sometimes, a person who has a dental problem or an injury to the bones of the jaw will have trouble swallowing saliva.
If you think you have more saliva than normal, see your doctor. Treatment will depend on the cause of the problem.