A brief attempt has been made to provide an overview of the field of heparinology. As stated, in coming years one should witness significant developments in this area. It is, however, important to caution that the newer products derived from heparin may not behave like heparin, and one must consider their individual molecular and biochemical interactions. The available limited data on heparin may or may not be applicable to the newer heparin fractions or derivatives. Independent preclinical and clinical trials are needed to investigate the pharmacology and therapeutic actions of newer heparin derivatives.