In this public lecture suitable for all ages, David Fox will draw upon his 18 years' experience as a medicinal chemist in the pharmaceutical industry to discuss how medicines work and the role chemistry plays in the design of new treatments for disease. The lecture will use a number of interactive demonstrations to illustrate the role of proteins in disease, how the structure and shape of compounds affects their biological activity and how viewing proteins and medicines in 3D aids our understanding of how they work. The lecture will also provide an insight into the process of medicines R&D, from the test-tube to the patient, with reference to current clinical candidates.