In January 1991 the winter meeting of the Surgical Research Society was held at St. Bartholomew's Hospital and the Institute of Education, London. During the meeting a symposium was held entitled 'Shedding light on lasers'. Speakers addressed the general principles of lasers, laser-tissue interactions and the applications of lasers in gastro-enterology and in vascular disease. This was followed by an open discussion of the current indications, complications and outcome, together with future possible applications for lasers in medicine.