The objective was to investigate the relationship between homocysteine (HCY), peroxisome proliferator-activated receptors (PPAR)-gamma and the expression of interleukin 6 (IL-6) and microsomal prostaglandin E synthase (mPGES) by peripheral blood mononuclear cell (PBMC) culture in vitro, as well as to look at the intervention with HCY and PPAR-gamma activators (troglitazone and rosiglitazone). PBMC were isolated from venous blood of normal volunteers and incubated with HCY and PPAR-gamma activator of varying concentrations for 24 hr. The supernatant of the culture medium was collected in order to determine the IL-6 and mPGES levels by ELISA assay. The results show that the expression of IL-6 and mPGES in the HCY experimental group was significantly higher than that in the control group (p<0.01 and p<0.05, respectively). Additionally, the IL-6 and mPGES levels rose with the increase of HCY in a dose-dependent manner (p<0.01 and p<0.05, respectively). PPAR-gamma activator could significantly inhibit the increase of IL-6 and mPGES induced by 100 micromol/L HCY (p<0.05 and p<0.01, respectively). In conclusion, HCY can increase the expression of IL-6 and mPGES, while PPAR-gamma activator can inhibit the increase of IL-6 and mPGES induced by HCY.