The most essential component when taking a surgical history before emergency surgery is current medications and allergies. This is critical because many medications, such as anticoagulants, can significantly affect surgical bleeding risk and anesthesia management. Allergies, especially to antibiotics or anesthetic agents, must be identified immediately to prevent potentially life-threatening allergic reactions during or after surgery. Understanding these factors ensures patient safety and appropriate perioperative planning in the limited time available before emergency intervention.

Reference: Sabiston Textbook of Surgery, Courtney M. Townsend Jr., 21st Edition.