(A) Histopathologic features of gingival specimens of the DMSO, nifedipine, and nifedipine plus Saireito groups. In HE-stained specimens, it was confirmed that the nifedipine-induced increase in the number of fibroblasts was inhibited by Saireito. In azan-stained specimens, it was clearly observed that Saireito decreased collagen formation and inhibited vessel enlargement. (B) The morphometric analyses of gingival overgrowth. There were significant differences in the area of connective tissue between the nifedipine and nifedipine plus Saireito groups and between the DMSO and nifedipine groups. *p < 0.05, ***p < 0.005, n = 3 (in each case).