Diarrhoeal diseases are a major cause of malnutrition, partly due to poor dietary practices. Misconceptions among the general population and medical personnel lead to withholding of food or avoiding the use of nutritious, locally available and affordable foods. Breast-feeding should not be interrupted during diarrhoea. Many recent studies have shown that when cow's milk is used, full-strength milk should be fed throughout the disease and in convalescence. The concept of diluting milk with water should be altogether avoided. If necessary, full-strength milk should be mixed with equal amounts of other foods. Other recent studies have shown that several diets based on local staples are excellent choices for the dietary management of diarrhoea. An all-vegetable diet commonly eaten in Guatemala produced a sharp decrease in the duration of acute diarrhoea (median duration after feeding began: 1.8 d) and its macronutrients were reasonably well absorbed. Practical recommendations are given, including nutritional, physiological, cultural and economic considerations.