Chloramphenicol is mostly used against coagulase-negative Staphylococcus aureus, and its protective role against coagulase-positive S. aureus is not well studied. In our study, arthritis was induced in mice by S. aureus (Apollo Gleneagles 33 (AG-33) or American Type Culture Collection 25923 (ATCC-25923)) infection. Chloramphenicol was administered after 2 h of infection. Mice were killed at 1, 3, 5 days post-infection. Mice inoculated with pathogenic Staphylococci (AG-33) expressing coagulase and Toxic shock syndrome toxin-1 (TSST-1), displayed severe arthritis with enhanced bacterial burden in the spleen, cytokine production in serum and synovial tissue, neutrophil recruitment, and cyclooxegenase-2 expression in synovial tissue compared with ATCC-25923-infected groups. Severity of arthritis was regulated by chloramphenicol treatment. Our study suggests that alteration in the inflammatory cytokine levels and pronounced production of cyclooxygenase-2 play important roles in progression of arthritis which is regulated by application of chloramphenicol. © 2010 Springer Science+Business Media, LLC.