The efficacy of methylprednisolone in reducing flap edema. It has been suggested that systemic steroids reduce postoperative flap edema. This has been poorly documented by several reports based on subjective clinical observations. In an effort to provide quantitative data on methylprednisolone and edema, a flap edema model in the rat was developed based on the inferior epigastric vessels. Significant edema developed after 48 hours. Differing intraoperative doses of methylprednisolone were studied, producing a dose-response curve. A single low dose of intraoperative steroid is effective in reducing flap edema; previously recommended doses are probably excessive. 