Used to treat hereditary angioedema (HAE), a rare genetic disorder causing sudden and severe swelling in various body parts including the limbs, face, intestinal tract, and airway. By replacing the deficient or dysfunctional C1 esterase inhibitor protein, it helps regulate the complement and contact systems, preventing uncontrolled inflammation and swelling attacks. It is administered intravenously during acute episodes or as prophylaxis to reduce the frequency of attacks. Particularly valuable in managing abdominal and laryngeal edema, which can be life-threatening. Also used in patients undergoing certain medical procedures where HAE flare-ups are a risk.