This study was conducted to evaluate the efficacy of Saccharomyces boulardii in acute diarrhea. One hundred hospitalized children in Myanmar (age range = 3 months to 10 years) were included. Fifty were treated with S. boulardii for five days in addition to oral rehydration solution (ORS) and 50 were given ORS alone (control group) in an alternating order. The mean duration of diarrhea was 3.08 days in the S. boulardii group and 4.68 days (P < 0.05) in the control group. Stools had a normal consistency on day 3 in 38 (76%) of 50 patients in the S. boulardii group compared with only 12 (24%) of 50 in the control group (P = 0.019). On day 2, 27 (54%) of 50 had less than three stools per day in the S. boulardii group compared with only 15 (30%) of 50 in the control group (P = 0.019). Saccharomyces boulardii shortens the duration of diarrhea and normalizes stool consistency and frequency. The shortening of the duration of diarrhea results in a social and economic benefits.