How can drooling occur in adults?

Hypersalivation. Causes of saliva overproduction include pregnancy, excessive starch intake, gastroesophageal reflux disease, pancreatitis, liver disease, serotonin syndrome, oral ulcers, and oral infections. Medications that can cause saliva overproduction include clozapine, pilocarpine, ketamine, and potassium chlorate. Toxins can also cause hypersalivation. These include mercury, copper, organophosphates, and arsenic.