Abstract: A method of digesting lignocellulose materials impregnated with solutions of hydroxides or salts of alkali or alkaline earth metals, the ratio by weight of the solution retained during the impregnation and the dry matter being less than 2, in a digester, characterized by subjecting the impregnated materials before the digestion to a treatment with live steam under a pressure equal to or greater than that present in the digester so that a part of the steam, by giving off its sensible heat to the impregnated material and condensing, assures the preheating and penetration of the impregnation liquor up to the center of the material. The time of digestion is shorter and the pulp obtained more homogeneous.