Abstract Background A minority of patients of acute hepatitis may exhibit edematous GB walls with no visible lumen despite fasting and may also exhibit paradoxical GB response in the post-prandial state. Methods Patients of acute hepatitis underwent routine upper abdominal sonography after overnight fasting. Patients who demonstrated contracted GB with edematous and coapted walls without any visible lumen despite overnight fasting were studied in the post-prandial phase after having breakfast. Serial ultrasonography was carried out at 10–15 min interval for an hour and changes in GB morphology was noted at each stage. Results A total of 77 patients of acute hepatitis underwent USG of hepatobiliary system between Sept 2008 and Aug 2009. Contracted gall bladder with edematous and coapted walls without any visible lumen despite overnight fasting was noted in 11 patients and were studied in the post-prandial phase. Post-prandial paradoxical filling of GB was observed in all such cases. Serial post-prandial ultrasonography demonstrated onset of filling of GB as early as 10–15 min post-prandial. Maximal GB distension was observed between 30 and 60 min. USG at 60 min post-prandial showed slight reduction in GB volume. As the GB distended in the post-prandial state, the lumen became increasingly visible with marginal reduction in wall thickening. Conclusion We have observed transient paradoxical filling of GB on serial USG in early post-prandial state, in a subset of patients of acute viral hepatitis who had contracted GB with coapted walls in the initial USG after overnight fasting.