NICE has issued new guidelines warning parents not to give fizzy drinks or even flat cola to children with diarrhoea and vomiting.
Health experts say that diarrhoea and vomiting is not helped by flat drinks, fizzy drinks or fruit juices, but dehydration should be avoided by giving children the right kinds of fluids.
Parents should give youngsters at risk of dehydration water with an oral rehydration salt solution.
NICE has issued the new advice to help parents manage gastroenteritis in children up to the age of five.
Each year GPs and hospitals deal with 150,000 to 300,000 cases of children under five in England, around 10% to 20%, who have symptoms of gastroenteritis.
When children end up dehydrated some may need hospital care but most children get better quickly without treatment and can be looked after at home.
Keep breastfeeding children who are not yet dehydrated, if they usually are breastfed, and keep fluids up, the guidelines advise.
However, the drinking of fruit juices and carbonated drinks should be ‘discouraged’, it said and while children who are dehydrated need a higher level care these drinks should still not be given.