Infants aged 3-21 months with acute diarrhea of bacterial and viral origin were treated as inpatients with oral rehydration fluid and randomly received for up to 6 days either a tannin-rich carob pod powder (40% tannins or 21.2% polyphenols and 26.4% dietary fiber), 1.5 g/kg/day (n = 21) to a maximum of 15 g, or an equivalent placebo (n = 20). The duration of the diarrhea from admission was 2.0 +/- 0.27 days in the test group and 3.75 +/- 0.30 days in the placebo group (p less than 0.001). Normalized defecation, body temperature, and weight and cessation of vomiting were reached more quickly by the patients who received the test substance. The test substance was well accepted and tolerated.