Oral rehydration solutions (ORS) have been used since 1960 and avoided millions of children deaths due to acute diarrhoeas. It is the only treatment currently able to prevent and treat acute dehydration. In France, ORS are cost free due to a health insurance refund. Its composition is regulated by law and the efficacy of each available product is equivalent. These products should be available in every infant's home, even before any gastroenteritis episode occurs. Parents should be aware of the risks of gastroenteritis in infants, also parents should know how to use ORS. The principle of use is to propose ad libitum the ORS as long as the diarrhoea continues. Breast feeding should be continued if going on. In cases of bottle feeding, milk should be reintroduced after a few hours of rehydration. ORS are not well known, prescribed or used and that may explain for the most part the dehydration and deaths which occur in France. ORS are the only life-saving treatment for gastroenteritis, which has proved its efficacy for the past 50 years: it is time to use it on a routine basis.