Wound-healing effect of St. John's Wort (Hypericum perforatum L.) extract was evaluated by comparing with dexpanthenol and titrated extract of Centella asiatica TECA) on cultured chicken embryonic fibroblasts. Chicken embryonic fibroblasts from fertilized eggs were incubated with the plant extract, dexpanthenol and TECA. Using microscopical methods by staining cells, mitotic ability, morphologic changes and collagen production in the cultured fibroblasts were evaluated as parameters to approach its mechanism of action in wound repair. Findings obtained in the present study indicated that Hypericum perforatum extract exhibited a wound-healing activity whose mechanism of action is similar to that of TECA. Wound-healing activity of Hypericum perforatum extract seems to be mainly due to the increase in the stimulation of fibroblast collagen production and the activation of fibroblast cells in polygonal shape, which plays a role in wound repair by closing damaged area. The findings demonstrated the wound-healing activity of Hypericum perforatum, which has previously been based on ethnomedical data. (c) 2006 Elsevier Ireland Ltd. All rights reserved.