For more than 25 years the World Health Organisation and UNICEF promote with an extraordinary success oral rehydration salts (ORS) solution to prevent or treat dehydration caused by diarrhoea. WHO supported over the years a number of studies in the effort to improve its composition. These studies resulted in the recommendation to use a new, lower osmolality formulation. This paper summarizes information about the results of studies using various ORS formulations and presents the WHO newly recommended composition in comparison to the recommendation of European Society for Paediatric Gastroenterology, Hepatology and Nutrition. The paper also briefly informs about the principles of treatment and prevention of dehydration in acute diarrhoeal diseases.

        Key words: oral rehydration salts, rehydration, dehydration, diarrhoea