The aim of the study is to assess impact of Fecal Microbiota Transfer (FMT) on clinical symptoms of Parkinson's disease. Assesment of tremor, slowness of movements and balance problems before and after FMT will be performed. The effect of FMT on frequency of constipations, which are common among Parkinson disease patients and have negative impact on quality of life and drug absorption will also be assessed. Detailed assessment of absorption of levodopa, which is the golden standard of treatment of Parkinson disease, is planned. It is planned to recruit 40 patients with diagnosis of Parkinson disease and indications for colonoscopy (constipations, age >50 years). Patients will be randomly assigned to the group receiving treatment with FMT or identically looking placebo. It will be administered to intestine during colonoscopy. Patients will be assessed by neurologist few times after the procedure. Psychological assessment and examination of gait and balance by physiotherapist is also planned. The last assessment will be performed after 12 months to see if the clinical effect can be observed for such a long time. The composition of the intestinal microbiota will be carefully assessed before and after the procedure in order to identify pathogens that may affect the course of the disease.

Inclusion Criteria:

• Idiopathic PD
• Consent to undergo colonoscopy

Exclusion Criteria:

• perforation or obstruction of gastroenteric tract,
• radiotherapy of abdomen or pelvis region
• severe heart, liver or kidney failure
• coagulation disorders
• immunity disorders
• current viral, bacterial or fungal infection
• abdominal aortic aneurysm qualifying for surgery, pregnancy and lactation treatment with Duodopa, deep brain stimulation or apomorphine
• colonoscopy confirmed colon polyps, except for lesions <5 mm qualified for the NBI International Colorectal Endoscopic I group or other potentially neoplastic lesions after evaluation in white light and narrow beam imaging (NBI)
• severe food allergy with a history of anaphylaxis after consumption of the product.
• microbiological stool evaluation with detection of: methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae carbapenemase (KPC), metallo-β-lactamase (MBL), extended-spectrum beta-lactamase (ESBL), vancomycin-resistant Enterococci (VRE), Salmonella, Shigella, Yersinia. If any other atypical pathogen are to be detected in general stool culture, it will be assessed on an individual basis.