Viscous fingering phenomena have long been studied both experimentally and theoretically in a very wide range of systems as reviewed by Bud Homsy in his classical paper in Ann. Rev. Fluid Mech 1987. This talk will review recent work devoted to the analysis of miscible viscous fingering in chemical systems. After recalling the important contributions of Bud Homsy in this context, I will discuss the negative influence that viscous fingering can have on the efficiency of chromatographic separation before describing the properties of chemically-driven viscous fingering dynamics.