Aim: Zinc is an adjunct to oral rehydration salts for management of diarrhoea in children. Due to zinc's unpleasant taste, children often develop nausea and/or vomiting. We aimed to assess acceptability (tolerability) and adherence of improvised formulation of zinc tablet among under-five children with acute diarrhoea. Methods: This was an open-label intervention trial among 3-59 months old diarrhoeal children attending the outpatient department of Dhaka Hospital, who were enrolled in two age strata, 3 to <18 months and 18-59 months. Zinc tablets 10 or 20 mg per day were prescribed for a total of 10 days for <6 months and ≥6 months age children respectively, with follow-up. Diary-cards were used to record events. Results: In stratum 1, 158 (90.8%) children and in stratum 2, 144 (95.4%) children completed the study as per protocol out of 325 enrolled children. Sociodemographic, clinical and anthropometric measurements were comparable in the two strata except admission diarrhoeal duration (median 3 days vs. 2 days, P = 0.001). Adherence to 10 days treatment was 123 (77.8%) in stratum 1 and 127 (88.2%) in stratum 2. Zinc tablets were tolerated very well/well in 280 (92.7%) children. Vomiting, regurgitation and nausea were observed in 99 (32.8%), 59 (19.5%) and 22 (7.4%) children respectively. Caregivers' willingness to use the same drug in future was 300 (99.3%) among all children. Conclusion: Our study findings demonstrate that modified taste and formulation zinc tablets were well tolerated, and caregivers' willingness to use this formulation in future supports its acceptability, adherence and palatability.