Following cardiac transplantation bacterial mediastinitis is a severe early complication. Between March 1986 and September 1993, cardiac transplant operations were performed in 101 patients, of whom six developed purulent mediastinitis. Treatment consisted of surgical débridement, closed local irrigation, drainage and systemic antibiotics. No patient died as a result of bacterial mediastinitis. Low cardiac output and requirements for resternotomy for bleeding and prolonged artificial ventilation were significantly higher in the group with sternal infection. In contrast, since January 1991 the dose of corticosteroid was decreased from 5 mg/kg per day to 1.5 mg/kg per day beginning on the first day after operation. A total of 51 heart transplant operations have been subsequently performed without sign of mediastinal infection.