Galaxies grow through the accretion of gas, minor mergers and major mergers in the hierarchical picture of galaxy evolution. The merging of two gas-rich galaxies cause gas to be driven towards the centres of the individual galaxies producing intense circum-nuclear star formation and creating a fuel reservoir for the accretion onto the central blackhole. Feedback due to supernova winds or AGN (Active Galactic Nuclei) accretion blows out the surrounding gas through an outflow at later merger stages, that may be large enough to deplete the galaxies of their fuel reservoir and hence shut down star formation and starve the central black hole. It is still uncertain what the impact of outflows is on merging galaxies, and when in the merging process they are most significant. This thesis used Integral Field Spectroscopy (IFS) observations of merging galaxies to probe the impact of outflows on gas-rich major mergers. Using velocity-resolved absorption and emission lines arising from the interstellar medium of the galaxies, this thesis presentation will show that the occurrence of outflows increases with merger stage and also that these outflows are not be caused by the same physical processes, such as starformation or an AGN, in each merger system.