Objective:To evaluate the efficacy of dexmedetomidine on painless gastroenteroscopy in the patients recovered from COVID-19.Methods:Eighty patients of either sex, aged 18-64 yr, with body mass index <30 kg/m 2, undergoing elective painless gastroenteroscopy, of American Society of Anesthesiologists physical statusⅠor Ⅱ, within 2nd to 7th weeks after diagnosis of COVID-19, who had a negative nucleic acid test or antigen test at present and presented with no respiratory symptoms in our hospital from January to February 2023, were selected and divided into 2 groups ( n=40 each) using a random number table method: dexmedetomidine group (group D) and control group (group C). Sufentanil 0.1 μg/kg was intravenously injected in two groups. Dexmedetomidine 0.2 μg/kg was intravenously injected in group D, and the equal volume of normal saline was given instead in group C. Propofol 1.5-2.0 mg/kg was intravenously injected after 2-3 min observation, and propofol 5-7 mg·kg -1·h -1 was intravenously infused to maintain sedation during operation. The development of bucking and hypoxemia during operation, total consumption of propofol, emergence time, time of hospital discharge, development of bradycardia and hypotension during operation, and scores for patients′ and endoscopic physicians′ satisfaction with anesthesia were recorded. Results:Compared with group C, the incidence of bucking and hypoxemia was significantly decreased, scores for endoscopic physicians′ satisfaction with anesthesia were increased ( P<0.05), and no significant change was found in the other parameters in group D ( P>0.05). Conclusions:Low-dose dexmedetomidine can reduce the risk of bucking and hypoxemia during operation and raise the quality of anesthesia in the patients recovered from COVID-19 undergoing painless gastroenteroscopy.