Parkinson's disease (PD) is a condition that affects the brain and is the second most common neurodegenerative disorder. Currently, there is no test to find PD early. This study aims to create a simple, non-invasive breath test to detect early PD. Breath contains tiny molecules that can help show if someone has a disease. By studying these molecules and changes in gut bacteria, researchers hope to find PD before symptoms appear. This could help start treatments earlier and improve patients' lives.

The study will look at volatile organic compounds (VOCs), small molecules in breath that can show how the body is working. The study will include 120 participants: 50 PD patients, 50 healthy controls, and 20 newly diagnosed PD patients not taking medication. They will collect samples like breath, stool, and blood to study.

• The study needs PD patients and healthy volunteers aged 18 to 90.
• Participants should not have taken antibiotics or probiotics in the last 4 weeks.
• No formal diagnosis of gut-related issues (dysbiosis) is allowed.