en Anesthesia Anesthesia Original Research Original Research <strong>Background: </strong>Various studies have shown the benefits of using glucocorticoids following surgery. However, side effects associated with drug administration have been investigated sufficiently. We aimed to evaluate the effects of different doses of dexamethasone on blood glucose concentration in patients undergoing elective abdominal surgery.<br> <strong>Methods:</strong> This double-blind clinical trial design study was conducted among 90 candidates of elective abdominal surgery referred to RasoolAkram Medical Complex&nbsp; in Tehran ,Iran, 2017-218. Patients included two groups of intervention: group I, received 4 mg dexamethasone; group II, received 8-10 mg dexamethasone; and group III (control group), received ondansetron after induction of general anesthesia. Data were analyzed using ANOVA, Kruskal-Wallis test, and repeated measures. &alpha;=0.05 was considered as a statistically significant level.<br> <strong>Results: </strong>The highest increase in blood glucose concentrations in all three groups occurred in the first 6 hours after the surgery. The lowest intensity of pain in all the groups occurred in the first 24 hours after the surgery. All the groups showed statistically significant changes in blood glucose concentration and pain intensity. Comparing among the mean blood glucose concentrations over time, there were statistically significant changes in time and group/time (p<0.001).&nbsp; Comparing the mean intensity of pain over time,&nbsp; statistically, significant changes were observed&nbsp; in&nbsp; time and group / time (p<0.001).<br> <strong>Conclusion:</strong> In general, change trends in blood glucose concentration and pain intensity could be dependent on the medication used and its dose, as well as the time of drug administration. Changes in blood glucose levels in the control group can be attributed to metabolic changes caused by surgical trauma.<br> &nbsp; Dexamethasone, Blood Glucose, Pain, Nausea, Abdominal Surgery 1214 1220 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-6641-1&slc_lang=en&sid=1 Poupak Rahimzadeh poupak_rah@hotmail.com 200319475328460066848 200319475328460066848 No Pain Research Center, Rasool Akram Medical Complex, Iran University of Medical Sciences, Tehran, Iran Nasim Nikoubakht nikoobakht.n@iums.ac.ir 200319475328460066849 200319475328460066849 No Pain Research Center, Rasool Akram Medical Complex, Iran University of Medical Sciences, Tehran, Iran Seyed Hamid Reza Faiz faiz.hr@iums.ac.ir 200319475328460066850 200319475328460066850 Yes Department of Anesthesiology and Pain Medicine, Minimally Invasive Surgery Research Center, Iran University of Medical Sciences, Tehran, Iran Mehrdad Khodabandeh khodabandeh.mehrdad@gmail.com 200319475328460066851 200319475328460066851 No Neuromusculoskeletal Research Center, Department of Physical Medicine and Rehabilitation, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran