Influence of variable viscosity the peristaltic flow of pseudoplastic fluid in a tapered channel is discussed. The effects of magnetohydrodynamics (MHD) are also studied. Asymmetric channel is considered. The relevant problem is first formulated and then non-dimensionalized. The nonlinear different system subject to lubrication approach is solved. Expressions for pressure gradient, pressure rise and velocity are constructed. Graphs reflecting the variations of sundry parameters on pressure rise and velocity are examined. Trapping and pumping phenomena are also studied.