Experimental data are presented for the flow of dilute and concentrated aqueous solutions of polyacrylamide through porous media. For the dilute solutions, an anomalous viscosity effect is reported. In order to examine the stress field in the porous medium, series of flow visualization experiments were performed describing two‐dimensional flow through groups of cylinders for both Newtonian and non‐Newtonian fluids. The differences in flow pattern were analyzed. From our results the dominating factor in the flow through porous media appears to be the presence of elongational stresses. As a conjecture, a simple modified expression of Darcy's Law which describes the data is presented.