Interleukin (i.l.)-8 levels in serial serum samples of 10 burned patients were analysed. The total body surface areas (TBSAs) of the burn injury ranged 30 to 85 per cent. Of these ten patients, five recovered and the other five, who were septic, died. On admission at about 5-13 h postburn, one of the five survivors and two of the non-survivors had serum IL-8 levels higher than 18.1 pg/ml, which is the detection limit of the IL-8 assay kit. The serum IL-8 values of six healthy laboratory personnel included in the present study were all less than 18.1 pg/ml. Afterwards, an initial peak serum IL-8 response was detected within 2-4.5 days postburn. Significant differences in the peak serum IL-8 levels were not found between patients with TBSAs of greater or less than 50 per cent and patients who survived or expired from burn injury. In the survivors, serum IL-8 remained low, whereas IL-8 increased markedly, starting at about one week postburn in four of the five non-survivors with confirmed sepsis. Significant differences in the maximum serum IL-8 levels were detected between patients who recovered vs. those who died from the thermal injury. In conclusion, the results showed that there was an increase in serum IL-8 postburn. Serum IL-8 was significantly higher in the septic patients, who all died. This cytokine may play a significant role in the pathophysiology of sepsis in burned patients.