During recent years, several cases of hemorrhage including subdural hematoma (Rowin and Lewis, 1996), subarachnoid hemorrhage (Vale, 1998), intracerebral hemorrhage (Matthews, 1998), have been reported to occur in coincidence with the use of Ginkgo products and those observations have generally been explained by the platelet-activating factor (PAF)-antagonistic action of ginkgolides. Here, PCLAF is linked to subarachnoid hemorrhage.