Overview of the worldwide problem of diarrhoea.

Acute infectious diarrhoea is the major killer of children in the Third World. It is also the principal cause of malnutrition in children under 5 years of age. More than 4 million children die each year of diarrhoea and its complications. Acute diarrhoea kills by causing dehydration, which leads to hypovolaemia and metabolic acidosis. Recurrent episodes of diarrhoea lead to malnutrition as the result of anorexia, catabolism from infection, and lack of adequate caloric and protein intake because of the widespread custom of 'starving' diarrhoea. Oral rehydration therapy (ORT) is effective in the prevention and treatment of dehydration caused by diarrhoea. Because it is cheap, easy to administer and very effective, ORT has the potential to allow substantial reductions in the morbidity and mortality of acute diarrhoea in children living in less developed countries. The major obstacles to achieving its potential are the social ones of production and distribution of oral rehydration solutions and of educating parents in how to use ORT.