This prospective, multicenter, randomized, double-blind, placebo-controlled clinical trial will evaluate the efficacy and safety of Escherichia coli 5C (Colipral®) in adult patients undergoing diagnostic colonoscopy. Participants will be randomized in a 1:1 ratio to receive either Colipral® or placebo for 14 days immediately after colonoscopy. The study aims to determine whether Colipral® reduces post-colonoscopy gastrointestinal symptoms compared with placebo, using validated symptom and stool assessment tools, patient-reported global improvement, and safety monitoring.

Patients undergoing diagnostic colonoscopy may experience gastrointestinal discomfort in the days following the procedure, which may be related to alterations in the intestinal microbiota induced by bowel preparation. This study is designed to evaluate whether supplementation with Escherichia coli 5C (Colipral®) can reduce post-colonoscopy gastrointestinal symptoms compared with placebo.

This is a prospective, multicenter, randomized, double-blind, placebo-controlled clinical trial. Adult patients undergoing complete diagnostic colonoscopy will be screened according to predefined inclusion and exclusion criteria and enrolled after written informed consent. Participants will be randomly assigned in a 1:1 ratio to receive either Colipral® or placebo for 14 days immediately following colonoscopy. The study treatment will be administered as 2 capsules per day, with 1 capsule in the morning and 1 capsule in the evening after dinner.

Clinical assessments will be performed at baseline and at 48 hours, 7 days, and 14 days after colonoscopy. The primary efficacy endpoint is the between-group difference in change in Gastrointestinal Symptom Rating Scale (GSRS) total score from baseline to Day 7. Secondary efficacy assessments include GSRS score changes at additional time points, numerical rating scale (NRS) symptom scores, stool consistency, bowel movement frequency, patient global impression of change, use of rescue medication, treatment adherence, tolerability, and adverse events.

The study is designed to assess both the clinical efficacy and safety of Colipral® in the management of post-colonoscopy symptoms in adult patients.

Inclusion Criteria:

• Age between 18 and 80 years
• Complete diagnostic colonoscopy with achievement of the cecal fundus
• Accepted written informed consent for study participation obtained prior to the start of the study

Exclusion Criteria:

• Chronic inflammatory bowel disease
• Complicated Diverticular Disease (DICA >3)
• Suspected or known colorectal malignancy on index colonoscopy
• Diagnosed microscopic colitis
• Operative colonoscopy
• Severe chronic gastrointestinal symptoms judged by the investigator to interfere with the evaluation of study endpoints
• Subjects who are immunosuppressed or on systemic immunosuppressive treatment, including patients with primary or acquired immunodeficiency, oncological disease on active treatment with chemotherapy/immunotherapy, or autoimmune diseases on immunosuppressive treatment
• Taking probiotics, prebiotics, or synbiotics within 2-4 weeks prior to enrollment
• Antibiotic therapy within 4 weeks prior to enrollment
• Lack of acceptance of written informed consent

This is a double-blind study. Participants, care providers, investigators, and outcome assessors will remain blinded to treatment allocation throughout the study. Active product and placebo will be matched in appearance and administration schedule.