Many drugs are used to prevent nausea and vomiting and pain after surgery. In this study the investigators will be looking at a drug, dexamethasone, which is commonly used to prevent nausea and vomiting and pain after surgery but has other side effects. Dexamethasone is a man-made drug that is commonly used during surgery but also can affect naturally occuring hormones. In this study the investigators will be looking at dexamethasone's effect on a number of naturally occuring hormones over a twenty four hour period after thyroid surgery. The investigators hypothesize that plasma cortisol levels will be decreased following administration of dexamethasone.