Clinical pharmacology in the UK in the 1950s and 1960s was an exciting profession. Many important new drugs were developed and brought to market and a more systematic knowledge of drug effects in humans was needed, as well as ensuring the safety and efficacy of new and existing drugs, especially following the unexpected problems arising from the use of thalidomide. This Witness Seminar followed an earlier meeting on the history of the general development of clinical pharmacology and focuses on the development of clinical pharmacology in pharmaceutical companies and drug regulation. Professor Rod Flower chaired the meeting of clinical pharmacologists and others who shaped the discipline, which discussed the main centres of influence; the attraction to clinical pharmacologists of working in industry; whether the decline in the number of academic clinical pharmacologists was paralleled in drug companies; what drove drug regulation; and the relationships between companies and regulatory authorities. Participants included Dr Jeffrey Aronson, Professor Nigel Baber, Sir Alasdair Breckenridge, Sir Iain Chalmers, Professor Joe Collier, Professor Donald Davies, Dr Peter Fletcher, Dr Arthur Fowle, Professor Sir Charles George, Professor David Grahame-Smith, Professor John Griffin, Dr Andrew Herxheimer, Professor Ray Hill, Dr Peter Lewis, Dr Tim Mant, Professor Denis McDevitt, Professor Michael Orme, Dr Anthony Peck, Professor Brian Prichard, Professor Sir Michael Rawlins, Professor John Reid, Professor Philip Routledge, Dr Julian Shelley, Dr Robert Smith, Professor Cameron Swift, Professor Tilli Tansey, Dr Duncan Vere, and Professor Owen Wade.