PIP: The efficacy of a commercial oral rehydration solution (ORS) was compared with that of the standard WHO formula ORS in treating infants hospitalized with acute diarrhea in Saudi Arabia. The commercial product contained less sodium and more glucose than the standard ORS. Among patients more than 2% dehydrated, 16 of 17 who received the standard ORS, were free of clinical signs of dehydration within 24 hours. Of 17 who received the commercial product, 9 needed intravenous therapy because of worsening dehydration. Patients on standard ORS had a greater mean weight gain in the 1st 8 hours and lower mean stool output. They showed significantly more rapid correction of acidosis and of azotemia, with higher intestinal absorption and urinary excretion of sodium. Diarrheal stools in patients on the commercial product were low in sodium and contained reducing substances, findings which suggest osmotic diarrhea from unabsorbed glucose.