19 critically ill adults with acute mediastinitis after cardiac surgery were treated with granulated sugar, either directly (11 patients) or after failure of continuous irrigation (8 patients). Mediastinal tissue cultures were positive in 18 patients. Packing the mediastinal cavity with granulated sugar every 3 or 4 h resulted in near-complete debridement of the wound and rapid formation of granulation tissue in all patients and sterilisation of the wound after an average of 7.6 days. Dressings were easy and painless to change. 5/19 (26%) patients died before discharge, but none because of wound complications. The rest were discharged on average 54.2 days (range 29-120) after initial debridement of the wound; 11 underwent secondary surgical closure of the wound and in 3 the wound healed by granulation tissue formation alone. No recurrence of sternal infection has occurred after a mean follow-up of 8.2 months (range 3 to 17).