@ patients scheduled for ambulatory LC with general anesthesia were randomly assigned to three groups : group A received @ mg parecoxib injection @-@ min before anesthesia induction and @ ml saline injection when gallbladder was removed ; group B received @ ml saline injection @-@ min before anesthesia induction and @ mg parecoxib injection when gallbladder was removed ; group C received @ ml saline injection @-@ min before anesthesia induction and the time when gallbladder was removed .