A number of studies suggest that keratinocyte growth factor (KGF) plays a major part in reepithelialisation after injury, via binding to the specific KGF receptor (KG;FR), Several pharmacological agents, including the anti-epileptic drag phenytoin (PHT), have been widely used clinically to promote wound healing. Although the mechanism of action of PHT in this process is still not well understood, it is possible that the activity of PHT in wound healing is mediated via KGF and the KGFR. In the present study, using the enzyme-linked immunosorbant assay and how cytometry we have shown that PHT increases KG:F secretion and KGFR expression by more than 150% in gingival fibroblasts and epithelial cells, respectively. Moreover, semi-quantitative reverse transcriptase-polymerase chain reaction analysis showed that PHT also markedly increased both KGF and KGFR gene transcription by these cells. Our findings thus suggest that the wound healing activity of PHT in vivo may be mediated, at least partly, via KGF and its receptor.