Physical models for the description of the hydrodynamics of trickle-bed reactors for foaming Newtonian and power-law liquids are virtually inexistent in the literature. An attempt is made in this work to develop a hydrodynamic model for cocurrent gas-liquid downflow involving foaming (non-)Newtonian power-law liquids through packed beds at non-ambient temperatures and moderate pressures. The model was an extension of the well-trodden slit model variants proposed for (non-)Newtonian power-law coalescing-liquid systems. Its validation using recently published experimental data [Aydin, B., and Larachi, F., 2008. Trickle bed hydrodynamics for (non-)Newtonian foaming liquids in non-ambient conditions. Chem. Eng. J. 143, 236-243.] allowed a quantitative representation of foaming flow hydrodynamics in terms of the two-phase pressure gradient and the liquid holdup up to 90 degrees C and 0.7 MPa. The model, requiring no arbitrary adjustable parameters, in addition related foam stability to quantitative descriptors such as the liquid-film-borne bubble holdup and diameter, and free (or headspace)-gas holdup. The model also exhibited logical and fully interpretable trends with regard to foam stability, reactor temperature and pressure, liquid and gas superficial velocities. (C) 2008 Elsevier Ltd. All rights reserved.