The results are reported of an experimental investigation of turbulent flow of a 1.5% Laponite solution, a shear thinning and thixotropic liquid, through a plane sudden expansion of expansion ratio R = 1.43 and aspect ratio A = 13.3. Two Newtonian fluid flows are also reported for comparative purposes. Apart from a slight effect on the reattachment length, caused by variations in the maximum turbulence intensity at separation, no major differences are found between the mean and turbulent flow characteristics of the Newtonian and Laponite fluid flows.