Abstract: The subject invention discloses a process for the preparation of a porous collagen matrix. Said process comprises providing a neutral or nearly neutral collagen solution, incubating the collagen solution at a temperature of between about 30 and about 45° C. for a period of time sufficient to reconstitute collagen fibrils to obtain a collagen gel matrix, freezing said collagen gel matrix with an appropriate temperature reduction rate to an appropriate freezing temperature, lyophilizing said matrix to form a porous collagen matrix and treating the lyophilized collagen matrix with an organic solvent that can quickly penetrate into the collagen matrix to prevent the shrinkage thereof.