Pediatric research in the management of nausea has been limited by the absence of a reliable method to quantify the intensity of this subjective symptom. In adults, the visual analog scale (VAS) is an accurate tool, but this has not been shown to be reliable in young children. A scale is a series of points made on a line that will be used for measurement; a mark on the far left of the line shows little pain and the mark on the far right means alot of pain.