Change in body temperature (delta BT) while dressings were being changed was measured in 52 extensively burned adults. The patients were divided into four groups based on outcome and the prognostic burn index (PBI; age + burn index): group I (15 survivors, PBI less than or equal to 80), group II (15 survivors, PBI between 80 and 120), group III (14 non-survivors, PBI between 80 and 120), and group IV (eight non-survivors, PBI greater than 120). The body temperature before the change of dressings was the same in the four groups. The mean(s.d.) delta BT in all patients was -0.5(0.8) degrees C. The magnitude of delta BT was not related to the time required for changing dressings (r = 0.04) or to the non-epithelialized area present at each change of dressings (r = -0.05). All groups showed a similar increase in delta BT during the early period after the burn, but in group I it began to decrease progressively after the 16th day after the burn (P < 0.05). A reduction in delta BT was noted in group II from day 25, whereas it was unchanged in groups III and IV (P < 0.05). It also significantly increased 2 days before the diagnosis of sepsis (P < 0.05). These results emphasize that delta BT may provide useful information about prognosis and the development of sepsis.