The invention relates to a chromatography method in which a gaseous, liquid or supercritical mobile phase containing species to be separated is circulated through a packing, said packing comprising: - a plurality of capillary ducts extending in the packing between an upstream face through which the mobile phase enters the packing and a downstream face through which the mobile phase leaves the packing, and - a continuous medium permeable to molecular diffusion extending between said ducts, comprising a porous organic gel or an organic liquid and including at least one network of connected pores, the size of which is greater than two times the molecular diameter of at least one species to be separated and opening to the ducts, so as to give said at least one species a diffusive path between said ducts. The invention also relates to a packing for the implementation of such a method and a method for manufacturing such a packing.