[en] The economic crisis has an adverse impact on health and nutrition of children. The prevalence of Protein Energy Malnutrition (PEM) was 33.4%, and severe malnutrition was 3.1%. In addition, diarrhea is also a big problem. Severe diarrhea affected 1.94 million of under five children in 1997, up from 1.75 million in 1995. Relationship of the magnitude of H. pylori infection with diarrhea and malnutrition will be investigated in this study. The study will be carried out in 3 phases in the district of Bogor, West Java, Indonesia. First year study: will include 40 severe PEM children. All subjects will be examined for H. pylori infection. Anthropometry and hematological analysis will be measured at the clinic. Dietary information, nutritional practices and the health of children will be gathered during home visits. Second year study: 34 children will be included. The mothers and their children will be asked to visit the clinic 12 times. At the clinic, the children will be treated, and the mothers will be given nutrition guidance. Home visits will be conducted for collecting nutritional practices, SES, and diarrhea infection. The examination of H. pylori infection, anthropometric measurements, and blood drawn for hematological purposes will be performed at the first visit to the clinic, and every 3 months thereafter Third year study: a total of 60 children (20 well nourished, 20 mild PEM, and 20 moderate PEM), aged 6 months to 3 years will be studied. They will be recruited in two Community Health Centres. All subjects will be examined for the magnitude of H. pylori infection, anthropometry, hematology, SES, nutrition practices and diarrheal infection. Statistical analysis will include means, SDs, correlation among variables, and covariant analysis will be made using SPSS Window software. (author)