Fig. (1) The figure represents groups of cells and molecules (Blood and tissue host cells, viral enzymes, snake venom enzymes) that could have close enzymatic and pharmacological interactions. The red ellipse represents blood components, clotting/fibrinolysis factors, and inflammatory mediators that are the resulting output of cells and enzymatic activations in the host body under physiological conditions or during pathological situations. Viral proteins and enzymes have close interaction with the host cells, starting from the priming of the S spike protein by host serine proteases. Blood coagulation/fibrinolysis enzymatic system involves many protease activities. Snake venom proteases, phospholipases and toxins interact with many host cells and blood components that lead to hemostasis dysfunction. The ellipse forms do not imply separate physical compartments in the host body. It is meant that foreign enzymes and molecules of invading organisms can pharmacologically interact with host enzymatic and molecular machinery, which leads to physiopathological events. * TMPRSS2: Transmembrane protease serine2. ACE2: Angiotensin converting enzyme 2. TF: Tissue factor. vWF: von Willebrand factor. tPA: Tissue plasminogen activator. PAI-1: Plasminogen activator inhibitor. PAF: platelet activating factor. NO: Nitric oxide.