INTRODUCTION: Despite the explosion of biological therapies, the old immunosuppressants continue to play a pivotal role in the management of inflammatory bowel diseases. AIM: To assess the appropriateness of immunosuppressants-azathioprine, 6-mercaptopurine, methotrexate, cyclosporine A, tacrolimus (FK506), mycophenolate mofetil and thalidomide-in the treatment of inflammatory bowel disease by using RAND/University of California Appropriateness Method. METHODS: The RAND method consists of a combination of evidence from the literature and experts' opinions. Appropriateness has been defined to mean that the expected health benefit exceeds the expected negative consequences by a sufficiently wide margin. A panel of 10 experts from the Italian Group for Inflammatory Bowel Disease has rated, in two rounds, on a scale from 1 to 9, the appropriateness of each indication selected by the Promoter Centre, on the basis of their own clinical experience. An indication was considered appropriate if the median of the panelists' ratings fell within the area 7-9, inappropriate in the area 1-3 and uncertain in the area 4-6. A total of 2781 indications were grouped into 13 categories (mild to moderate Crohn's disease; severe Crohn's disease; fistulizing Crohn's disease; steroid-dependant and -resistant Crohn's disease; maintenance of remission induced by medical treatment in Crohn's disease; maintenance of remission induced by surgery in Crohn's disease; mild to moderate ulcerative colitis; severe ulcerative colitis; steroid-dependant and -resistant ulcerative colitis; maintenance of remission induced by medical treatment in ulcerative colitis; extra-intestinal manifestations in inflammatory bowel disease; pregnancy and inflammatory bowel disease; azathioprine-resistant or -intolerant inflammatory bowel disease patients). RESULTS: Of the 2781 scenarios, 212 (7.6%) were rated appropriate, 645 (23.2%) uncertain and 1924 (69.2%) inappropriate. The most relevant results were: in steroid-dependant or -resistant Crohn's disease, azathioprine, 6-mercaptopurine and methotrexate were defined as appropriate in 25 (86.2%) and 14 (48.3%) of the 29 scenarios respectively; in Crohn's disease, azathioprine and 6-mercaptopurine were defined as appropriate combined with Infliximab (bridge therapy); in steroid-dependant or -resistant ulcerative colitis, azathioprine and 6-mercaptopurine were defined as appropriate in 45 (77.6%) out of 58 scenarios, while methotrexate was defined appropriate only after previous azathioprine failure; in severe ulcerative colitis, cyclosporine A was defined as appropriate only after previous failure with steroids; in azathioprine-intolerant or -resistant inflammatory bowel disease patients, methotrexate was appropriate in 20 (66.7%) out of 30 scenarios; it is inappropriate to stop azathioprine treatment before conception in the presence of active disease. The use of FK506, mycophenolate mofetil and Thalidomide resulted as inappropriate or uncertain. CONCLUSIONS: Results of this study show that only azathioprine, 6-mercaptopurine and methotrexate are appropriate in the treatment of inflammatory bowel diseases. Cyclosporine A was found to be appropriate only in severe ulcerative colitis after the failure of steroids. FK506, mycophenolate mofetil and Thalidomide resulted as inappropriate but experience with these agents is somewhat limited.