The present invention relates to a method for preparing a growth-factors containing platelet releasate from a fluid mammalian platelet concentrate, comprising the consecutive steps of subjecting the platelet concentrate to a pathogen reduction step to disrupt non-enveloped viruses； subjecting the platelet concentrate to an activation step to cause the platelets to release growth factors； recovering a fibrinogen depleted fluid platelet releasate； subjecting the fibrinogen depleted fluid platelet releasate to a second pathogen concentration reduction step to disrupt enveloped viruses； subjecting the platelet releasate to sterile filtering and recovering a filtrate liquid containing the growth factors. The platelet releasate obtained with the method of the present invention may be used as a therapeutic agent to enhance the proliferation of multi lineage cells in regenerative medicine and in the management of non healing wounds and resistant ulcers. The second indication is as a substitute to fetal bovine serum in in cell culture media.
