The primary source of pathogens causing diarrhea is fecal contamination of food, water, hands, and objects in the household; mothers, particularly through their role in preparing food, are at the center of this cycle of contamination. A complete program of diarrhea control, therefore, includes not only oral rehydration therapy (ORT) to combat the effects of diarrhea, but water supply and sanitation programs which ensure the safety of water used to mix ORT solutions and which train health workers to educate women in promoting personal, domestic, and food hygiene. Such programs should be introduced before introducing ORT; this will require coordination within the host government health ministry, between the health ministry and the water supply agency, and within A.I.D.'s ORT and water sanitation programs. The planning of such programs must take account of the primary roles of women and peripheral health workers in delivering ORT and sanitation services, the legal responsibilities of country ministries in these areas, and the need for low-cost water supply schemes. Two pages of references (1955-85) in French and English are provided.