We determined the effect of complete excision and closure of the burn wound on the postburn increase in oxygen consumption. Twelve sheep were given a 15% of total body surface full-thickness burn and were monitored for 7 days. By the third day, a 50% increase in O2 consumption, VO2, was noted, as was a significant increase in cardiac index and decrease in mixed venous PO2, compared to baseline. The hypermetabolic process persisted for the 7-day pre-excision period. On the seventh postburn day all sheep were anesthetized for 2 hours with halothane and placed on positive pressure ventilation, and then one half of these sheep underwent excision and closure. During anesthesia, VO2 decreased to 76 +/- 15 ml/min/M2, a value significantly lower than even the preburn awake baseline of 122 +/- 14 ml/min/M2 and the 7-day postburn value of 180 +/- 18 ml/min/M2. Quantitative cultures, before excision, revealed the wounds to be noninfected (less than 10(5) organisms per gram). In six animals, the burns were totally excised to fascia and closed with full-thickness defatted hide from other sheep obtained at the same time under sterile conditions. In these animals, the VO2 returned to preburn baseline by 24 hours postexcision and remained there for the 3-day postexcision study period. In the other six burned sheep, the 15% full-thickness burns remained. The hypermetabolic state returned to the 7-day postburn level on return to the awake state and persisted for the remainder of the study. We conclude that complete excision and wound closure can reverse the postburn increase in O2 consumption.