Efficacy and Safety of 1 L PEG-ASC Preparation for Colonoscopy in Patients with Inflammatory Bowel Diseases: A Multicenter Observational Study

<b>Background/Objectives</b>: The effectiveness of 1 L PEG-ASC preparation in inflammatory bowel disease (IBD) patients is still unclear. The aim of this study was to determine the efficacy and safety of 1 L PEG-ASC in a series of IBD patients. <b>Methods</b>: Data from a study conducted on a series of 284 patients collected in three centers between 2020 and 2025 were analyzed. The primary outcome was cleansing success whereas success in the right colon, polyp detection, adverse events, and patient reported outcomes were secondary endpoints. <b>Results</b>: The mean age was 43.28 ± 12.21 years and 170 (59.8%) patients were male. Out of 141 ulcerative colitis (UC) patients, 45 (32%) presented with a Mayo score of 3. The Mean Simple Endoscopic Score Crohn's Disease (SES-CD) score in CD patients was 7.2 ± 7.04. Overall and right colon cleansing success were reported in 267 patients (94.2%), of which 134 CD (93.9%) and 133 UC (94.6%) patients (<i>p</i> = 0.81). The overall BBPS score was 7.47 ± 1.44, specifically 7.52 ± 1.23 in CD and 7.40 ± 1.62 in UC patients (<i>p</i> = 0.76). Overall, 19 patients (6.7%) were diagnosed with polyps with a mean number of polyps per colonoscopy of 0.08 ± 0.03. The preparation was completely taken by 264 (92.9%) patients, and 247 patients (86.9%) declared their willingness to repeat the bowel preparation. Severe nausea was observed in 1 (0.3%) patient and no other severe adverse events were recorded. <b>Conclusions</b>: The 1 L PEG-ASC preparation is well-tolerated and safe in IBD patients.