The method of obtaining collagen as above, is characterized by this, that the process of cleaning the skins is done manually using tools made of natural materials such as glass and wood to remove from the skins scales, skills and meat tissue so prepared raw material is placed in a solution of lactic acid of 0.1 to 1.5% concentration, obtaining hydration of collagen contained in the skins. The hydration process is carried out in glass containers, in the temperature from 15 to 20.degree. C., for 24 to 48 hours, conducting a running visual control of the process. Next follows an operation of filtration using silk filters of increasing density. By repeated filtering the cell elements, pigments and remains of the acid solution are removed from collagen. The natural silk filters have a structure similar to the structure of collagen, which prevents damage to the collagen structure.