BACKGROUND: Dexamethasone has a prophylactic effect on postoperative nausea and vomiting (PONV) and perioperative hydration is believed to play a role in PONV prophylaxis. This study was performed to examine the combined effects of pre-induction dexamethasone plus super-hydration on PONV and pain following laparoscopic cholecystectomy (LC). METHODS: A total of 100 female patients undergoing LC were enrolled and randomized equally into two groups. Group DF received 5 mg dexamethasone (pre-induction) plus 30 ml/kg Ringer's lactate (intraoperative) and group D received 5 mg dexamethasone (pre-induction) alone. Anesthetic and surgical managements were standardized for all patients. The incidence and severity of PONV, and intra and post-operative analgesic and postoperative antiemetic consumption, were assessed during the first 24 h postoperatively. Post-anesthesia care unit (PACU) stay and aggregated 24 h pain scores were calculated. RESULTS: Group DF had significantly lower PONV than group D (P = 0.03). The number of patients with the lowest PONV score was significantly increased in group DF (P = 0.03). Ondansetron consumption was significantly lower in group DF (P < 0.0001). The mean accumulated 24 h pain scores were significantly lower in group DF compared to group D (P < 0.0001). The time to first analgesic request was significantly longer in group DF than group D (P < 0.0001). In addition, total meperidine consumption during the first postoperative 24 h was significantly lower in group DF than group D (P = 0.002). CONCLUSIONS: In female patients undergoing LC, pre-induction with 5 mg dexamethasone plus intraoperative 30 ml/kg Ringer's lactate solution decreased PONV and pain during the first 24 h postoperatively compared to 5 mg dexamethasone alone.