Hemostatic agents (HAs) can be absorbable, biological, or synthetic. Absorbable HAs, like gelatin or oxidized cellulose, speed up clotting and are naturally absorbed by the body. Biological HAs include thrombin, fibrinogen, and platelets which are key to blood clotting. Synthetic HAs, such as polyethylene glycol, form strong sealant matrices. The choice of HA depends on the type of bleeding, tissue interaction, and patient's coagulation profile. Instruments like the ElastoSens™ Bio provide valuable data on HA efficacy by measuring blood absorption and coagulation kinetics.