Gingival hyperplasia is frequently associated with the long-term use of phenytoin for control of convulsive disorder. The purpose of this study was to investigate on the effects of lipopolysaccharides (LPS), ursolic acid and oleanolic acid to phenytoin-induced cell activity in human gingival fibroblast. Human gingival fibroblasts were cultured form the healthy gingiva of orthodontic patients. Gingival fibroblasts were trypsinized and transferred to the weels of microtest plates. Fibroblast were cultured in growth medium added $5{mu}g/ml$ of phenytoin, $5{mu}g/ml$ of LPS, $10^{-7}M$ of ursolic acid and oleanolic acid. The passage number of cultured fibroblasts were fifth and eight. Cell morphology was examined by inverted microscope and the cell activity was measured by proliferation assay. Ursolic acid significantly modulated cell morphology into globular shape at the concentrantion of $10^{-7}M$ in the presence of phenytoin and LPS, and the cell activity was significantl decreased by ursolic acid or oleanolic acid regardless of the presence of phenytoin and LPS. These results suggested that the increased phenytoin-induced cell activity might be modulated by ursolic acid regardless of the presence of phenytoin and LPS. These results suggested that the increased phenytoin-induced cell activity might be modulated by ursolic acid or oleanolic acid. Further study is needed to clarify their toxicological effects on cellular modulation and mRNA expression change.