Participants will be recruited if they have Parkinson's disease, Parkinsonism. Inclusion and exclusion criteria are summarized below. Participants will be screened at the first visit to make sure they are eligible for the trial. They will then undergo baseline testing including neurologic evaluation, questions to assess their memory and cognitive status and evaluation of their disease status using parts of the Unified Parkinsons's Disease Ratings Scale (UPDRS) that are routinely used to follow disease progression. They will be given a questionnaire to evaluate the severity of their drooling. Their saliva production will be measured by having them spit into a cup for 5 minutes, twice.