Pharmacists active in health care venues need to be able to evaluate generic drugs in terms of effectiveness, safety, and economy to ensure that they are used appropriately. As part of the ongoing study of these factors, we carried out an objective evaluation of information provided for generics. A minimum of 20 commercially available products was considered for each pharmaceutical ingredient. The information subjected to evaluation consisted of the text of drug package inserts and information noted on interview forms. Using our own criteria for evaluating drug information, we attempted to quantify the amounts of information provided. Then, based on the numerical values obtained, we calculated information quantities with reference to drug prices to study the relationship between prices and available information for original drugs and their later-developed, generic equivalents. A total of 14 different pharmaceutical ingredients (327 product items) were considered, with the information quantity for generics amounting to 27.9+/-17.8-46.3+/-21.4% (Mean+/-S.D.) that for the original drugs. Examined on the basis of individual pharmaceutical companies, the corresponding ratio came to 15.1+/-7.8-62.4+/-6.4% (Mean+/-S.D.). For generics, the relationship between drug price (expressed against a value of 1.0 for original drugs) and information quantity (Qua(i)) came to 0.79+/-0.46-1.90+/-0.79% (Mean+/-S.D.). These results clearly point to the importance of evaluating information quantity for generic drugs on a maker-by-maker basis.