Dexamethasone was first reported to be an effective antiemetic regimen in patients receiving cancer chemotherapy. Some authors have reviewed the available randomized trials (1996-2001) regarding perioperative single-dose steroid administration and found that dexamethasone had antiemetic and analgesic effects in various types of operations. One ot this studies demostrated that intravenous dexamethasone at 4 mg was effective for the prevention of PONV following breast surgery but they could not demonstrate any difference in postoperative pain.