Improved surgical outcomes have been achieved as a result of preoperative risk assessments and developments in surgical and anaesthetic techniques. However, post-operative haemorrhage remains a life-threatening complication requiring swift recognition and management. This article explores the compensatory mechanisms the body employs during haemorrhage and how these may present as altered observations that can aid early recognition. It also describes the rapid assessment of patients using the ABCDE (airway, breathing, circulation, disability, exposure) approach and outlines the management interventions used to halt the bleeding and restore intravascular volume.