The aim of this study was to evaluate the infl uence of diltiazem in combination with a sucrose-rich diet on gingival alterations in rats. One hundred and twenty male Holtzman rats were randomly assigned to 10 groups (n = 12), being 2 control groups treated with saline and 8 test groups treated with diltiazem in daily doses of 5, 25, 50 and 100 mg/kg during 40 or 60 days. Afterwards, the mandibles were removed for macroscopic, histologic and histometric analyses of the buccal gingiva of the mandibular right fi rst molar. No macroscopic characteristic of gingival overgrowth was observed in any of the groups. The microscopic analysis showed characteristics of normality with infl ammatory cells only adjacent to the crevicular epithelium in all groups for both periods. The histometric analysis showed signifi cant differences only for the epithelial tissue area in the 40-day period (Kruskal-Wallis; P = 0.032). Comparing the periods, signifi cant differences regarding the connective and epithelial tissue areas were observed only in the group treated with a 25 mg/kg dose (Mann-Whitney; P = 0.004 and P = 0.007, respectively). Oral administration of diltiazem in combination with a sucrose-rich diet did not induce gingival alterations in rats.