In the 1960s, researchers discovered a revolutionary formula that has saved the lives of millions of children around the world: Oral Rehydration Solution (ORS). ORS is a deceptively simple combination of natural sugars, table salt and small amounts of necessary chemicals such as potassium. It's cheap, and it's even possible to make ORS at home. But, as Rose Hoban reports, it's not always the solution of choice for some parents.

Mixed with water, ORS is given to children with gastroenteritis ? diarrhea or vomiting ? and is usually more effective at treating these problems than any other drug.

But doctors have long noted that some parents don't give ORS to their children. Instead, they give them carbonated drinks that are no longer fizzy. Doctor Ashley Reece, a pediatric emergency physician at Watford General Hospital in Hertfordshire, England, sees this use of "flat" soda frequently. He says there's a public myth that flat carbonated drinks are good for kids with diarrhea and vomiting. "It's something that we would call an old wives' tale," Reece says, noting that family members or neighbors might pass along the advice.

Reece thought that this use of carbonated drinks was inappropriate. So, he and a colleague set out to review all the literature they could find on how useful carbonated drinks, such as colas, really are for children with diarrhea or vomiting. They reviewed dozens of articles and found no evidence that carbonated drinks are effective for treating children with gastroenteritis.

"What we did find was a lots of evidence about the biochemical composition of carbonated drinks, [as] compared to oral rehydration solution," Reece says. "And the outcome of these studies shows that there is not enough minerals, not enough sodium, potassium, for example, in carbonated drinks compared to what's recommended in oral rehydration solution? and they contain far too much sugar."

Reece says children who are dehydrated from vomiting or diarrhea need these minerals. Potassium, for example, is necessary to keep the heart beating regularly.

He says it's tempting to give children medicine that they will tolerate, and that they will like. "Because of the high levels of sodium, for example, in the oral rehydration solution, it isn't that palatable," Reece admits. "However, if the child is dehydrated, usually we find that they will drink it and we have ways that we can try of putting small amounts in so that we get enough volume in over a required amount of time."

Reece concludes that even though ORS seems too simple to be good, it is the right thing to give children with gastroenteritis.

His research is published in the Archives of Disease in Childhood, the Journal of the Royal College of Pediatrics and Child Health.