Effect of Probiotic on Constipation in Patients With Parkinson's Disease

Inclusion Criteria: * A positive diagnosis of functional constipation or Irritable Bowel Syndrome -subtype constipation according to Rome IV criteria. * Negative for colon cancer screening * Negative relevant additional screening or consultation whenever appropriate. * Ability of conforming to the study protocol. * Stable treatment for Parkinson's disease Exclusion Criteria: * Presence of any other relevant organic, systemic or metabolic disease (particularly significant history of cardiac, renal, oncology, endocrinology, metabolic or hepatic disease), or abnormal laboratory values that will be deemed clinically significant on the basis of predefined values a part from Parkinson's disease * Ascertained intestinal organic diseases, including ascertained celiac disease or inflammatory bowel diseases (Crohn's disease, ulcerative colitis, diverticular disease, infectious colitis, ischemic colitis, microscopic colitis). * Previous major abdominal surgeries. * Inability to conform with protocol. * Recent history or suspicion of alcohol abuse or drug addiction. * Previous participation in this study.