Abstract: Objective: To compare the effects of nitrous oxide and intravenous anesthesia with propofol in colonoscopy. Methods :103 patients were randomly divided into two groups:the propofol intravenous anesthesia group( group A) and the nitrous oxide group(group B). Observe and compare the blood pressure、pulse oxygen saturation and the performing time of colonoscopy and the time of recovery and the rate of adverse reaction of the two groups. The datas between two groups were compared and statistically analyzed with software SPSS 11.5. Results :group B has shorter recovery time compared with group A,the difference was statistically significant （P<0.05）;the A,B group has no significant difference in vital signs before and after examining and discomfort (P> 0.05). Conclusion: Both nitrous oxide inhaled and propofol intravenous anesthesia can all relieve discomfort in colonoscopy, further more using nitrous oxide has shorter recovery time.

Key words: Nitrous Oxide, Propofol, Anesthesia & Analgesia, Veins, colonoscopy