Standardized deep partial-thickness burns were inflicted on domestic pigs by scalding 30 per cent of the skin surface for 25 s with 75 degrees C hot water. The animals (n = 18; weight 25-35 kg) were divided into three groups: I, control group (n = 6), Ringer's lactate only; II, haemodialysate group (n = 6), Ringer's lactate and a protein-free haemodialysate of calf-blood (ACTIHAEMYL20%; AH) and III, C1-inhibitor group (n = 6), Ringer's lactate and C1-inhibitor (C1-INH; BERINERT). Skin biopsies were taken at defined time points (4, 28, 52 and 76 h) and investigated histologically. Depth of burn was determined morphometrically after coloration with a modified MTT-staining on frozen sections of the skin biopsies. Fluid therapy with C1-INH decelerated significantly the progression of the burn wound in the postburn-period compared to Ringer's lactate alone. In comparison with C1-INH, the treatment with AH demonstrated a less beneficial influence on the depth of scald burns. The favourable effects of C1-INH are explained by the protection of the dermal microcirculation during the acute phase of thermal injury.