Oral rehydration therapy is the only treatment recommended by the World Health Organization in acute diarrhea in children. The aim of this study was to compare the efficacy and safety of a therapy with gelatin tannate plus oral rehydration versus oral rehydration alone in children with acute gastroenteritis.

This is a single-blind, prospective, randomized and parallel study performed in two Pediatric Services of tertiary referral hospitals. Patients, ages 3 to 36 months with acute gastroenteritis randomized to receive an oral rehydration solution (OR), or an oral rehydration solution plus gelatin tannate (OR+G). The primary outcomes evaluated were: the number of bowel movements after 48 and 72 hours after initiating treatments. Secondary outcomes were: duration of diarrhea (days), stool characteristics and adverse events. Other clinical variables, as weight, fever, vomiting, appetite and the acceptability of the two treatments were also recorded.

Inclusion Criteria:

• Children of both sex, aged 3 months to 5 years of age
• Clinical diagnosis of acute gastroenteritis, as defined by having at least 3 loose stools within the previous 24 hours and/or a change in stool consistency to loose or liquid according to Bristol Stool Form Scale for Children (m-BSFS-C) lasting for no longer than 3 days.

Exclusion Criteria:

• patients with gastroenteritis lasting more than 5 days
• patients with chronic gastrointestinal conditions
• patients receiving other antidiarrheal drugs within 2 weeks prior to enrollment (i.e. antibiotics, probiotics, salicylates, loperamide, racecadotril, disomectite)