Diarrhoeal disease is the second leading cause of death in children, killing 1.5 million children every year. Malnourished children suffer most. Rotavirus, Escherichia coli, Shigella, Campylobacter, Salmonella, Vibrio cholerae and Cryptosporidium are the major pathogens that cause diarrhoeal disease in children. The tremendous incidence of diarrhoeal diseases in malnourished children underscores the urgent need for interventions, such as food-based oral rehydration salt (ORS) treatment. This review gives a summary of major pathogens that cause diarrhoeal diseases in poor nations and discusses the use of food-based ORS solutions in the treatment of dehydration in malnourished children.