The management of nausea and vomiting requires an understanding of the probable mechanism and logical consideration of drug selection.  It also requires an approach that is individualised to the emotional and psychological needs of the child and family.

The evolutionary purpose of vomiting is to expel ingested toxins before they can do damage.  Vomiting gives the body several opportunities to do this:

• Even the smell or sight of something nauseous can evoke a powerful emetic response (anticipatory nausea).
• Once a toxin is ingested, emesis can be initiated by any or all of the gastrointestinal tract, the liver, or the brain.
• Vomiting is mediated by a series of receptors and neurochemicals, modified (and often amplified) by emotional and psychological input from higher cortical centres, co-ordinated by a specialised centre of the brain, and finally effected via the vagus nerve.