Urea Breath Test A breath sample will be collected for base line 13 CO2 in a vacutainer following a fasting period of 2 hr. A volume of 100 ml of whole milk will then be allowed to be consumed by the children. Ten min later 40 mg of 13 C urea (99% 13C, Tracer Technologies, Boston, Massachusetts) will be given after dissolving in 25 ml of water. After administration of the substrate, breath samples will again be collected in duplicates after 30 min. Samples will be collected through two-way pediatric mask with an attached non-return valve into a vacutainer and will be stored for shipment to the University of Alabama, to measure the 13C concentration of a respiratory CO2 mass spectrometer. The excess over the baseline will be expressed as parts per thousand(delta 0/00). A breath test in which the excess over a baseline is 5.00/00 at 30 min will be regarded as positive for H. pylori infection.