Little information was available on the epidemiology and etiology of diarrhoeal diseases in pre-school children in U.A.E. Geographically considered as part of the developing world, the U.A.E. could have been expected to have developing world problems - diarrhoea being one of them. This study was conducted to determine why diarrhoea was not at present a leading cause of infantile mortality and morbidity in the study area and to examine the impact of the major health-related interventions on the health-care system. Various sources of information and approaches to analysis were used: 1. Government statistics-information was obtained from the various government departments that collaborated in the interventions made. 2. Background data for the laboratory studies was obtained from routine clinical laboratories at Jazeira Hospital, Central Hospital and the maternity hospital. 3. Qualitative data was derived from observations made during the home visits to the study families for the six month study period, and included reviews with family members. Historical recollections were collected from older people as to the social conditions prior to the oil boom. 4. Quantitative data were obtained from the questionnaire that was administered to a group of study families and from laboratory analysis of specimens collected from these families over the study period. Government sponsored interventions at the primary health-care level seemed to have been successful in preventing diarrhoea. This was probably made possible by the explosion of wealth and affluence that came with the oil-boom and the accompanying change in life-style and attitudes, which made possible the provision of clean water and a sewage system, thus cutting the most important routes of infection.