Anaphylaxis is a serious potentially life-threatening systemic hypersensitivity characterised by airway, breathing and/or circulation compromise. Where feasible, any trigger should be removed. Hypotensive patients should be placed in a supine position with or without leg elevation but those with airway or breathing compromise may prefer to sit up. A standard adrenaline dose of 500 micrograms (0.5 ml of 1:1,000 adrenaline) is recommended in adults, whereas dosage varies in children depending on age/weight.