The present study was performed to investigate the effects of Jin-Ying-Tang (JYT), a Chinese herbal formula containing Lonicera japonica, Herba taraxaci, Fructus trichosanthis, Fructus forsythia, Radix et rhizoma rhei, Astragalus membranaceus, Angelica sinensis, on rabbit mastitis induced by Staphylococcus aureus. Suckling rabbits were challenged with 1.5 × 10(7) colony forming unit (CFU) of S. aureus at the base of the third pair teats, and they were treated and pretreated with JYT to detect the formula effects. The results showed that JYT could reduce the occurrence of Staphylococcal mastitis in rabbit model. To further investigate the action mechanism of JYT, we examined the leukocyte counts and inflammatory mediator levels such as TNF-α and IL-6 in blood and infected tissue. From histological study and blood analysis, we found that JYT could suppress leukocyte infiltration in infected mammary gland tissue and significantly inhibit the total leukocyte counts and lymphocytes (LYM), monocytes (MON) and granulocytes (GRA) fractions of leukocyte counts in blood. Enzyme-linked immunosorbent assay (ELISA) results showed JYT significantly decreased the TNF-α and IL-6 concentrations in serum and mammary gland. The analysis of these data suggested that JYT effectively inhibited inflammatory responses to reduce the occurrence of mastitis in rabbit model.