The goal of this review is to briefly summarize the two primary pathways of hemostasis, primary hemostasis and secondary hemostasis, as well as to summarize anticoagulant mechanisms and fibrinolysis. In addition, this review will discuss pathologies of hemostasis and the mechanisms of the various drugs that are available to impact these pathways to prevent either thrombosis or bleeding. While many of the main drugs that are used to treat disorders of hemostasis have been used for decades, greater understanding of hemostasis has led to development of various new drugs that have come onto the market recently or are close to coming onto the market. Thus, improved understanding of hemostasis continues to lead to benefits for patients.