Hypoglycaemia is a potentially serious complication of diabetes mellitus in which an individual’s blood glucose drops to dangerously low levels. This can cause signs and symptoms such as sweating, confusion and unusual behaviour and, if untreated, may lead to unconsciousness and death. Hypoglycaemia is a side effect of some treatments for diabetes, whereby injected insulin or oral medicines that stimulate insulin secretion cause an abnormally low blood glucose level. Nurses have an important role in educating and empowering patients and their families and carers to manage diabetes to prevent hypoglycaemia, and to initiate prompt treatment of this complication.