This article studies the effects of various supercritical fluids on the weight losses of lignocellulosic materials with the data reported by Li and Kiran (1988). It is found that the solvent effect on the weight losses is of less importance than the thermal degradation reactions In the absence of water. In the presence of water at about 190 degrees C and 29 MPa, the reaction order is 0.5 with respect to water mole fraction.