Clinical Research Directory

Inclusion Criteria: Participants with Parkinson's disease 2. Community-dwelling patients with newly diagnosed PD who have not yet started medication for Parkinson's disease. Control Participants 1\. Healthy (non-Parkinsonian) members of the participants household will be invited to act as controls. Exclusion Criteria: 1. Use of oral or intravenous antibiotics in the last 8 weeks. 2. Active gastrointestinal disease, not including constipation or irritable bowel syndrome without other symptoms. 3. Current use of medications which cause/worsen constipation e.g., opioids, tramadol, gabapentin, pregabalin. 4. Potential controls will be excluded if they report prodromal symptoms of PD, such as anosmia or rapid eye movement (REM) sleep disorder or display parkinsonian signs on examination. 5. Inability to give informed consent at any stage of the study e.g., because of dementia.