Gamma-ray tomography and a liquid collecting device have been used to detect liquid spreading from a single point source in a trickle bed. This basic configuration has been chosen to evaluate the radial spreading of liquid flow through a fixed bed. The experimental data are used to validate the two-dimensional (213) computational fluid dynamic model (CID) developed at the CREL laboratory for gas/liquid trickle flows inside a fixed bed [Jiang et al., 2002. A.I.Ch.E. Journal 48, 701-730]. The data obtained show the influence of liquid and gas flow rates and the impact of pre-wetting condition on liquid distribution evolution along fixed bed axis. The comparison between experimental data and simulation results shows a significant effect of the capillary pressure term on prediction of the radial spreading of the liquid flow. Several physical models for the capillary pressure term are tested in order to select the closure law that allows a proper prediction of liquid spreading at trickle flow conditions. (c) 2005 Elsevier Ltd. All rights reserved.