We propose to conduct such a study among children living in El Paso, Texas, a city located on the U.S.-Mexico border. A series of studies have been conducted in that city by the authors of this proposal, including a National Institutes of Health sponsored study aiming to describe the natural history of Helicobacter pylori infection in children from birth to age seven years (84 months). We hypothesize that the Helicobacter pylori bacterium decreases iron from the stomach and that this effect of the infection can be identified among persons with iron deficiency as well as among persons with normal iron stores. Currently, the clinical management of the most extreme form of iron deficiency, that is iron deficiency anemia, relies only on supplemental iron therapy. For ethical reasons, our study will identify children with anemia from the study, and will assign them to one of the arms receiving iron supplementation. Our study will determine whether a combination of iron supplementation and sequential Helicobacter pylori eradication therapy yields higher increases of iron stores than each of these treatments alone. To summarize, our main hypothesis is that Helicobacter pylori infection is associated with iron deficiency such that Helicobacter pylori eradication would result in an increase in the levels of: