Objectives: To examine whether PHGG added ORS reduce duration of diarrhoea, stool output and enhance weight gain. Methods: In a double-blind controlled clinical trial, 126 malnourished children (weight for length/weight for age < -3 Z-score with or without pedal edema), aged 6 - 36 months with acute diarrhoea < 7 days were studied in two treatment groups; 63 received modified WHO ORS (Na 75, K 40, Cl 87, citrate 7, glucose 90 mmol/L) with PHGG 15 g/L (study group); 63 received modified WHO ORS without PHGG (control). Other treatments were similar in both groups. The study protocol was approved by Ethics Committee of icddr,b; the study was carried out at the Dhaka Hospital. Results: The mean duration of diarrhoea (h) was significantly shorter in children of the study group (Study vs. control, mean +/- SD, 57 +/- 31 vs. 75 +/- 39, p = 0.01). Although there was a trend in stool weight reduction in children receiving ORS with PHGG (study vs. control, stool weight (g), mean +/- SD; 1st 24 hour, 854.03 +/- 532.15 vs. 949.11 +/- 544.33, p = 0.32; 2nd 24 hour, 579.84 +/- 466.01 vs. 761.26 +/- 631.64, p = 0.069; 3rd 24 hour, 385.87 +/- 454.09 vs. 495.73 +/- 487.61, p = 0.196), especially in 2nd 24 h period, the difference was not statistically significant. The mean time (day) to attain weight for length 80% of NCHS median without edema was significantly shorter in the study group (study vs. control, mean +/- SD, 4.5 +/- 2.6 vs. 5.7 +/- 2.8, p = 0.027). Conclusion: PHGG added to ORS substantially reduced duration of diarrhoea. It also enhanced weight gain. Further studies might substantiate to establish its beneficial effect.