Awareness of variations in the delivery of medical care has resulted in considerable research activity focused on developing measures to assess the appropriateness of health service provision both internationally and within Great Britain. As in other areas of health service provision there is evidence of variation in advice provided alongside sales of non-prescription medicines and variation in response to requests for advice about the treatment of minor ailments within community pharmacies in Great Britain. However, there is little research which has explored the extensive methodological problems associated with developing criteria to assess the appropriateness of these two activities. Following a critical review of relevant existing research, this paper describes a methodology and empirical findings from a study which aimed to develop criteria to measure the appropriateness of advice provided in community pharmacies. Firstly, details of advice-giving episodes occurring between consumers and pharmacists or medicines counter assistants were captured and documented using a combination of audio tape-recording and non-participant observation. Secondly, the nominal group technique was used to develop a set of explicit criteria for assessing the appropriateness of advice. Thirdly, an assessment instrument was developed in order to operationalise the criteria. The devised criteria include both process and output components. We discuss the utility of these criteria in relation to developments in self-medication practice affecting community pharmacy and the deregulation of medicines within the UK. The criteria have been subject to rigorous statistical testing to establish standards of validity and reliability (Ward, Bissell & Noyce, 2000a [Ward, P. R., Bissell, P. & Noyce, P. R. (2000a). Criteria for assessing non-prescription drug therapy in community pharmacy, Annals of Pharmacotherapy (in press).]). The developed criteria will allow us to identify dimensions of both appropriate and inappropriate advice provided in community pharmacies and provide the basis for education and training initiatives identified as a result of the research. In addition, we suggest that this research is highly relevant to informing the content, structure and operationalisation of protocols and/or guidelines associated with the management of minor ailments and the sale of medicines through community pharmacies.