This study compares the influence of methylprednisolone with that of a placebo on post-operative pain and swelling, and on healing. Twenty patients undergoing the removal of symmetrically placed bilateral lower third molar teeth under local analgesia by the same operator one side at a time were used. In each individual patient, for one side 40 mg methylprednisolone (Solumedrone Upjohn Limited) was given intravenously immediately preoperatively and for the other side a placebo was given on a double-blind random basis. The results showed that the mean post-operative swelling at 24 hours was reduced by 56% (p = .0003) when methylprednisolone was used compared with the opposite side of the same patient when the placebo was used. The severity of pain also was reduced over the first day but healing was similar for each side. Sixteen patients indicated a preference for the overall post-operative course when methylprednisolone was used.