Background: Sufficient distension of the GI lumen is needed for safe advancement of endoscopes and for careful visualization of the mucosa. Carbon dioxide (CO₂) has been proposed as an alternative to room air for insufflation. Aim of the Study: To assess the merits and demerits of the use CO₂ insufflation for endoscopy in terms of safety and efficacy. Methods: Electronic and manual searches were combined to search RCTs (Randomized controlled trials). After methodological quality assessment and data extraction, the efficacy and safety of CO₂ insufflation were systematically assessed. Results: Ten RCTs met the eligibility criteria and included in the present study; six of which on colonoscopy, two on endoscopic retrograde cholangiopancreatography (ERCP) and two on double-balloon enteroscopy (DBE). Postprocedural pain was assessed. Overall, pain was lower in the CO₂ insufflation group compared with the air group. Two RCTs found decreased flatus in the CO₂ group compared with the air group, and 3 RCTs showed there was decreased bowel distention on abdominal radiography in the CO₂ group compared with the air group. Moreover, CO₂ insufflation revealed no consistent advantages in the RCTs of DBE, yet it was still indicated safe as air insufflation in stomach/ oesophagus endoscopic submucosal dissection. PCO₂ level showed no significant variation during these procedures. Conclusion: CO₂ insufflation is proven to be associated with decreased postprocedural pain, flatus, and bowel distention. CO₂ insufflation also appears to be safe in patients without severe underlying pulmonary disease.