Comparison of the mean basal and nadir pH during gastro-oesophageal reflux (GOR) episodes with regional intragastric pH. *Gastric pH significantly higher than nadir pH (***p < 0.005); †gastric pH significantly lower than nadir pH (†p < 0.05, ††p < 0.005, †††p < 0.0005). Comparison of the mean basal and nadir pH during gastro-oesophageal reflux (GOR) episodes with regional intragastric pH. *Gastric pH significantly higher than nadir pH (***p < 0.005); †gastric pH significantly lower than nadir pH (†p < 0.05, ††p < 0.005, †††p < 0.0005). T I Omari, and G P Davidson Arch Dis Child Fetal Neonatal Ed 2003;88:F517-F520 Copyright © BMJ Publishing Group Ltd & Royal College of Paediatrics and Child Health. All rights reserved.