Etiology of Excessive Bleeding Excessive bleeding can result from several mechanisms (see table Some Causes of Excessive Bleeding), including the following: Platelet disorders Coagulation disorders Defects in blood vessels Platelet disorders may involve: an abnormal number of platelets (typically too few platelets, although an extremely elevated platelet count may be associated with excessive bleeding): defective platelet function, often due to drugs such as aspirin, P2Y12 inhibitors (eg, clopidogrel): or nonsteroidal anti-inflammatory drugs (NSAIDs), or both an abnormal number and defective function of platelets.