Antibiotic resistance is one of the world’s most pressing health problems. The available antibacterial treatments are becoming less and less effective as the pathogens become increasingly drug resistant, making the discovery of new treatments and therapies urgent. Multidrug resistant strains of Gram negative pathogens rely on tripartite protein assemblies that span both the inner and outer membranes to pump cytotoxic compounds from the cell. These macromolecular protein complexes form highly efficient drug efflux pumps that confer resistance to the pathogen against a wide range of structurally diverse compounds including clinically relevant drugs. We are using a multi-pronged approach consisting of modelling, molecular biology and subsequent biochemical and biophysical analysis to gain a better understanding of how drug transporter proteins work. In addition, we are applying this knowledge to investigate the possibility of developing inhibitors of the efflux pumps from natural products. Our data on the molecular mechanism of drug efflux proteins and our successes with identifying novel efflux pump inhibitors will be summarised.