Full thickness burns(20% TBSA)was produced in male Wistar rats.Liver mitochondrial function was determined polarographicallly on the 9th daypostburn(PB).In another group of animals,burn eschar was removed on the 9thday PB and extracted with 0.9% NaCl solution(CEBE).Extract of normal ratskin(ENS)was prepared similarly.Liver mitochondria were prepared fromnormal rats and incubated with CEBE or ENS.The respiratory function wasthen determined.It was found that the respiratory control ratio(RCR)in the burned animalswas much depressed(63.7%)as compared with the normal value.In the secondset of experiment,RCR was also inhibited in the CEBE-treated mitochondria,mainly due to the elevation of the state 4 respiration rate.The RCR value in theENS-treated mitochondria also showed certain degree of inhibition but it wasmuch weaker than that in the CEBE-treated group(P<0.01).The inhibitoryeffect was totally absent in higher dilutions in the ENS group while in theCEBE-treated group slight but definite inhibition was found up to the dilutionof 1:512.Energization of inner membrane was also affected by CEBE(3 experiments).When normal mitochondria were incubated with CEBE,the“blue shift”phenomenon was either diminished or totally absent.Besides,the extent ofdecrease of the maximal absorbancy was much smaller than that of the controlsafter the administration of substrates.Slight inhibitory effects were also observedin more concentrated suspensions of ENS.The mechanism of this inability ofmembrane energization was briefly discussed. Full thickness burns (20% TBSA) was produced in male Wistar rats. Liver mitochondrial function was determined polarographical ly on the 9th day postburn (PB). In another group of animals, burn eschar was removed on the 9thday PB and extracted with 0.9% NaCl solution (CEBE) .Extract of normal ratskin (ENS) was prepared similarly. Liver mitochondria were prepared fromnormal rats and incubated with CEBE or ENS. The respiratory function wasthen determined. It was found that the respiratory control ratio (RCR) in the burned animals was much depressed (63.7%) as compared with the normal value.In the secondset of experiment, RCR was also inhibited in the CEBE-treated mitochondria, mainly due to the elevation of the state 4 respiration rate. The RCR value in theENS-treated mitochondria also showed certain degree of inhibition but it was much weaker than that in the CEBE-treated group (P <0.01). The inhibitory effect was totally absent in higher dilutions in the ENS group while in the CEBE-treated group slight but definit e inhibition was found up to the dilution of 1: 512. Energization of inner membrane was also affected by CEBE (3 experiments) .When normal mitochondria were incubated with CEBE, the “blue shift” phenomenon was either diminished or totally absent.Besides, the extent of decase of the maximal absorbancy was much smaller than that of the controls after the administration of substrates. Slight inhibitory effects were also observedin more concentrated suspensions of ENS. the mechanism of this inability ofmbrane energization was briefly discussed.