To ascertain the existence and quality of evidence of the value of medicines in the UK a case study approach was adopted. METHODS: Four disease areas which feature in the UK "Health of the Nation" strategy were chosen: Cardiovascular disease; HIV/AIDS; gastric/peptic ulcer disease; and mental illness. A literature review was undertaken to identify 3-5 studies in each disease area which produced evidence of cost-savings to the health care system or cost-effectiveness in delivering patient benefits. The studies were assessed for economic methodological quality using a scoring system adapted from Rapier and Hutchinson (1995) for relevance/influence on clinical practice as determined by a panel of clinicians; and for significance to patients by interviews with patient group representatives. RESULTS: Most of the studies scored well on the methodological test (<13 out of a maximum of 15). Influence on clinical practice was not necessarily related to the quality of the economic analysis. The importance of the clinical problem and the nature of the clinical evidence on which an economic study was based played a large part. Patients' perception of benefits did not always concur with that of the clinicians. Whilst there was consensus on the value demonstrated in some studies, particularly in HIV/AIDS and ulcer treatment, there was a divergence of view in many cases between the economists/clinicians on the quality of studies. Clear evidence of cost-saving was difficult to find, but evidence of cost-effectiveness acceptable to all three groups was identified in several areas. CONCLUSION: The results of this study show: the need to identify problems as perceived by patients/clinicians; the need to ensure that the clinical audience understands the nature/purpose of economic evaluations; and the need to use the most appropriate study design/evaluation methods.