Aprotinin is widely used as an antifibrinolytic agent in surgical settings to reduce blood loss during procedures involving significant bleeding, such as cardiac surgery with cardiopulmonary bypass, liver transplantation, and major orthopedic surgeries. It works by inhibiting plasmin, an enzyme responsible for breaking down blood clots, thereby helping to maintain clot stability and reduce the need for blood transfusions.

In addition to its use in surgery, aprotinin has been applied in cell culture and biotechnology to protect proteins from degradation by proteolytic enzymes. It is often included in protein extraction buffers to prevent unwanted proteolysis.

Aprotinin is also used in research to study the role of serine proteases in physiological and pathological processes, including inflammation, vascular permeability, and tumor progression. Despite its benefits, clinical use has been limited in some regions due to concerns over increased risk of renal dysfunction and cardiovascular complications, leading to careful patient selection and monitoring when used.