Phospholipase A2 (PLA2) is the main allergen of hymenopteran venoms. We describe a highly efficient reverse phase high performance liquid chromatographic method (HPLC) for isolating PLA2 from crude bee venom. This method removes all detectable contaminants such as melittin from PLA2 while preserving the hemolytic action of PLA2. In addition we describe a simple functional assay of PLA2 based on its propensity to cause hemolysis of guinea pig red blood cells. These techniques are particularly well suited to the isolation and assessment of PLA2 of venoms which are available in limited quantities.