The present invention relates to a free parietal fraction of Propionibacterium acnes and granulosum, obtained by delipidation and controlled crushing of the strain ATCC51277 or DSM20458. Said free fraction is particularly useful as an immunomodulating agent for a series of pathologies, being further characterized in that it has a high inhibitory effect against the symptoms associated with disorders. The fraction obtained can moreover be formulated in pharmaceutical compositions for local topical use, for example in gels.