The results of the present study clearly indicated that the administration of captopril, a renin-angiotensin system inhibitor, effectively suppresses the development of AOM-induced colonic preneoplastic lesions in diabetic and hypertensive SHRSP-ZF rats by decreasing the serum levels of AT-II and colonic epithelial expression levels of ACE and AT-1R mRNA. This evidence concerns the gene ACE and infectious otitis media.