Over the span of the last few days, there have been more and more illnesses from seasonal flu. This year, the most unpleasant and dangerous type strikes an essentially great number of peaople. An acute stomach-intenstinal catarrh, accompanied by vomiting, stomach aches and fever contribute to numerous hospitalisations and turn a vacation into a nightmare. Each of these symptoms may occur separately, but the risk of dehydration appears when all of them come together and is higher while they concern a younger person. The infants and young children who fall ill with stomach-intenstine catarrh, accompanied by fever, are more prone to hydroelectrolite disorders which may lead to a life-threatening dehydration.