This WHO manual is appropriate for use by managers of health programs in controlling the dietary intake of young children with acute diarrhea. diarrhea is a major cause of malnutrition because of the low food intake during the illness, reduced nutrient absorption, and increased nutrient needs from the infection. Those most at risk are young infants 4-6 months old, who are not breastfed, and older infants and children (4-6 months to 2 years old). The introduction presents the causes of diarrhea, causes of malnutrition, and recent findings on nutrition in young children and mothers and on the digestion and absorption of nutrients during diarrhea. The selection of foods to be given during and after diarrhea is discussed in terms of the following variables which affect the choice of foods: age of the child, availability of foods, resources needed for food preparation, nutritional value of food, stage of illness, consistency of food, and frequency of feeding.^ The role that traditional beliefs and practices play in treatment is also mentioned as is the nature of the beliefs. Foods are classified as food and nonfood, appropriate and inappropriate foods, cultural superfood, special occasion foods, and foods related to ideas concerning physiology. Common treatments for diarrhea are starving the child for a short time; partial food restriction; continuation or restriction of breastfeeding; the feeding of certain foods, at certain times, and in specified amounts; the administration of herbal drinks and plant infusions; and the use of purgatives, emetics, or magical potions. It is important to collect information from several sources in communities and to gather data from discussions, written records, and observation. Methods to prevent diarrhea include following good feeding practices, washing hands after defecation, and keeping the children clean.^ Monitoring children on a growth chart to diagnose specific nutrient deficiencies, particularly of vitamin A and iron, helps in determining malnutrition. The multimix principle in introducing weaning foods is given, and a table provides a list of important nutrients as well as a list of foods rich in these nutrients. It is of particular importance during diarrhea to consume potassium-rich foods, carotene-rich foods, and milk and to avoid sweetened drinks.