PIP: A major criticism of the use of oral rehydration solution (ORS) in the treatment of diarrhea has been that the high sodium content of the solution might predispose the development of hypernatremia in infants not allowed access to additional free water and in whom glomerular filtration rate and urinary concentrating ability may be low. A study was undertaken in 1980 in Cairo, Egypt to assess the use of ORS. The study included 100 children under age 1, mean age 6.7 months, with dehydration secondary to diarrhea, and 17% were hypernatremic on admission, 27% hyponatremic and 56% isonatremic; the hypernatremic infants were found to be more dehydrated than the others. 24% of the hypernatremic infants had taken Rehydran whereas only 5% of the others had taken it and none had been given the medication in a proper fashion. Of the 17 with hypernatremia 16 completed the course of oral rehydration therapy and 63% had normal serum sodium values by 6 hours of therapy. It was found that the treatment of hypernatremic infants with ORS was successful while with the unsupervised use of Rehydran the risk of this condition was enhanced; errors made in the home included prolonged use of the solution and failure to use water. It is believed that because of widespread illiteracy sole reliance upon written instructions is potentially dangerous.