Intro Dental caries has often been described as a disease related to the use of diet although, as a multi-factorial disease, oral bacteria, tooth enamel composition and salivary components and consistency are also major factors. Until the 1970s various models were used from human intervention studies, observational studies and attempts to recreate intra-oral conditions with in vitro systems, artificial mouths, plaque pH, animal models, clearance/retention studies and enamel demineralisation. All these were tried with varying degrees of success. The formation of the Food, Nutrition and Dental Health Program of the American Dental Health Foundation in 1970 became the basis of a series of research studies, properly controlled and conducted, to assess which methods of evaluation of the cariogenic potential of foods were the most appropriate and reliable. These studies culminated in an international conference in San Antonio (USA) in 1985 published by Hefferren. At the San Antonio conference the participating scientists involved agreed on the two main methods available, animal models and plaque pH, but also determined that enamel demineralisation should be further developed as a model. Dental erosion was not perceived as a problem, at that time, and was not mentioned in the deliberations. The animal model has continued to be used. Researchers, and other authorities, wishing to determine the cariogenic potential of foods, drinks and some oral medicines, have used the plaque pH models. The enamel demineralisation model, often called the intra-oral cariogenicity test (ICT), has been further developed since the San Antonio conference, so that it is now widely used for cariogenicity testing. Variants of the ICT, also known as the in situ model, are now being developed to test foods and drinks for erosion, but need evaluation. Method On 8 and 9 November 1999, a group of dental scientists and clinicians met in London (UK) to review the San Antonio recommendations, reassess them and draw up revised guidelines. The aim was to determine which methods are currently suitable as research tools but also for regulatory assessments. The conference was directed by Professor John Hefferren, previously Chairman of the San Antonio meeting, and who lead the discussions of all delegates. In each of the four workshop sessions, under the guidance of a chairman, a presenter gave a prepared report to update the information on a particular method or group of methodologies. Each presentation was then commented on by a reactor and then by open discussion of all delegates. On the second day individual workshops were held involving small groups of delegates and working documents prepared presenting draft new guidelines. In a final plenary session all of the working documents were reconsidered and refined. Subsequently, the chairman of each working group was asked to prepare a draft document that was then circulated and commented upon by all delegates. After final editing the consensus opinions are presented in this document.