BACKGROUND: Anti-inflammation, anti-bactericidal, and collagen synthesis are important for health skin conditions. However, the effect of horse oil on anti-inflammation, anti-bactericidal, and collagen synthesis is largely unknown. OBJECTIVE: The aim of this study was to evaluate the anti-bactericidal, anti-inflammatory, and synthesis of type I collagen of horse oil. METHODS: Anti-bacterial effect was evaluated by disc diffusion test. Expressions of inflammatory cytokines were studied by RT-PCR analysis, real time PCR. Type I collagen expression was evaluated by Western blot in human HaCaT kertinocytes and fibroblasts. RESULTS: Our data showed that horse oil exerted anti-bacterial effect on P.acnes and S.aureus. Expression of IL-10 was increased by horse oil-treated HaCaT cells. In addition, increased expression of type I collagen was observed in horse oil-treated human skin fibroblasts. CONCLUSION: Horse oil exerts an anti-bactericidal effect against P.acnes and S.aureus. In addition, anti-inflammatory and anti-aging effects of horse oil will be mediated by up-regulation of IL-10 and type I collagen, respectively.