By means of a case/control study, an attempt was made to identify the different questionnaires and biological tests which might be used in the General Practice consulting room for the detection of alcoholic patients. A comparison was made between the CABE, MALT, and Skinner questionnaires, and the MCV, AST, ALT, GGT triglyceride, cholesterol, uric acid, bilirubin and glycemia biological tests. Sensitivity, specificity, predictive value and diagnostic efficiency were studied in a group of 37 confirmed alcoholics and 25 controls making up a population with a high prevalence of alcoholism. Later we analysed the changes which affect the values of the different tests when applied to a population with a low prevalence of alcoholism, in other words, the utility of the tests in general practice was evaluated. The study concludes that the diagnostic performance of the questionnaires together with case history is higher than that of biological tests in general practice, and that the routine application tests in general practice, and that the routine application of the CAGE questionnaire and to a lesser extent of the Skinner questionnaire make it possible to identify those patients suspected of alcoholism and to improve the predictive value of the biological tests applied thereafter. Nevertheless further study is necessary to confirm the diagnostic effectiveness of these questionnaires in the general population of health centre patients.