Knowing how the body reacts to the presence of pathogens allows healthcare professionals to make informed decisions about what action to take in caring for the child with fever. A raised body temperature raises the metabolic rate and makes the immune response more efficient. It also stimulates naturally occurring anti-pyretics but can also have harmful effects. Careful monitoring based on risk of serious illness is recommended in new guidelines on the management of feverish illness in young children provide (National Institute of Health and Clinical Excellence (NICE 2007), which also provide an opportunity for standardising fever management.