This study was performed to investigate the wound healing effects of Allium cepa L. on Staphylococcus intermedius contaminated wound. 4 full-thickness skin wounds ($2;cm{ imes}2;cm$) were made in the back and Staphylococcus intermedius was inoculated in seven dogs. In each dog, the wounds were treated with onion extract (experimental group) and normal saline (control group), respectively. The wound contraction rate of the experimental group was higher than that of the control group during the experimental period. The occupation rate showed that the wounds of the experimental groups contracted more vigorously than that of the control group in the early period of wound healing. The mean value of tensile strength on the 22 day after wounding was $4,741{pm}848;g/cm^2$ in the experimental group and $2,400{pm}397;g/cm^2$ in the control group. The number of S. intermedius in the experimental groups was decreased more rapidly than that of the control group. These results suggest that application of activated onion extract in like full-thickness skin wounds promote wound healing.