Current medications and behavioral modifications have limited success in the treatment of functional constipation (FC). An individualized diet based on microbiome analysis may improve symptoms in FC. In the present study, we aimed to investigate the impacts of microbiome modulation on chronic constipation. patients fulfilling Rome IV criteria for functional constipation were randomized into two groups. The Control group received sodium picosulfate plus conventional treatments (i.e., laxatives, enemas, increased fiber, and fluid intake). The study group underwent microbiome analysis and received an individualized diet with the assistance of a soft computing system (Enbiosis Biotechnology®, Sariyer, Istanbul). Differences in Patient Assessment Constipation-Quality of Life (PAC-QoL) score and complete bowel movements per week (CBMpW) were compared between groups after 6 week-intervention.

Inclusion Criteria:

• Patients fulfilling Rome IV criteria for functional constipation (FC)
• Patients who had a colonoscopy performed within the last 5 years
• Patients who had a colonic transit time assessment within the last 3 months
• Patients who had a magnetic resonance defecography within the last 3 months

Exclusion Criteria:

• Use of antibiotics, probiotics, and/or prebiotics within the last 4 weeks
• Gastrointestinal endoscopy within the last 4 weeks
• Major gastrointestinal surgery (total/segmental gastrectomy, small bowel and/or colonic resection)
• Cholecystectomy
• Inflammatory bowel diseases
• Celiac disease
• Any etiology of chronic constipation other than FC (irritable bowel syndrome, rectocele, dyssynergic defecation, opioid use)
• Endocrine, metabolic or neurologic disorders causing constipation (hypothyroidism, Parkinson's disease, paraplegia)