Holger Stark is a member of various pharmaceutical and scientific societies and organizations, such as the (DPhG), in which he was chairman of the Hessen state group from 2004 to 2013. Since 2014, he has led the DPhG state group Rheinland. He is also a member of the German Chemical Society (GdCh), the European Histamine Research Society (EHRS) and the Frankfurt Pharmacy School e.V., which he co-founded.
