Abstract
Anaxagoras and Empedocles both established during the Presocratic era a pioneering theory for the creation of everything in the universe. Macrocosmos' impact through the "Four Elements Theory" explained the conglomeration of the blood inside the vessels. Hippocrates, who instituted the "Four Humours theory", clearly understood blood's coagulation and introduced the term "thrombus". Plato, Aristotle and Galen, all engaged with the clotting phenomenon trying to interpret it. After eons of inquiry, it was the innovative thinking of the ancient Greek medico philosophers that set the scientific bases towards the understanding of a process that had been analyzing until our era.
Keywords: Blood, clot, thrombus, coagulation, empedocles, hippocrates, aristotle, galen, ancient greece.