Background Increased levels of interleukin-6(IL-6)and C-reactive protein(CRP)have been reported in patients with venous thromboembolisms(VTE).However,prospective studies did not confirm an association between IL-6,CRP and their polymorphism with the risk of V-TE.Methods One hundred and forty patients(including 66 males and 74 females,mean age(55.55±17.11)years)and one hundred and sixty controls(including 74 males and 86 females,mean age(56.58±12.24)years)were involved.An enzyme linked immunosorbent assay(ELISA)method was used for detecting the serum levels of inflammatory factors IL-6 and CRP in both groups.Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)was used for analyzing the distribution of polymorphisms at the-572C/G and-597G/A sites of the promoter of the IL-6 gene and at 1059G/C of the CRP gene.Results Serum levels of IL-6 and CRP were significantly higher in the VTE group than in the control group(P＜0.05).The frequencies of-572C/G promoter polymorphisms CC,CG,and GG in the IL-6 gene were found to be 34％,48％,and 18％,respectively,and the derived allele frequencies for the C and G alleles were 58％ and 42％.There was a significant difference in the-572C/G promoter polymorphisms between the VTE group and control group(P＜0.05).For the-597G/A polymorphism,individuals all carried the GG and GA type;AA genotypes were not detected.The frequency of the GG,GC,and CC genotypes at the CRP1059G/C promoter was 87.57％,7.86％ and 3.57％ in VTE group,while 86.25％,10％,and 3.75％ in control group,respectively.The frequency of G and C alleles at CRP 1059G/C was 91.43％and 8.57％ in VTE group and 91.56％ and 8.44％ in the control group.The results showed that there was no statistically significant difference of 1059G/C genotype and mutation frequency of the allele between the VTE group and control group(P＞0.05).Multiple Logistic regression analysis showed CC homozygotes of the IL-6-572G/C,body mass index(BMI),and CRP,IL-6,and high-density lipoprotein cholesterol(HDL-C)were independent risk factors for VTE(P＜0.05).Conclusions We found that VTE was associated with IL-6 and CRP levels,and there was an association of IL-6 and its promoter polymorphism at-572G/C with the risk of VTE.Thus far,a causal relationship between inflammation and VTE remains to be clarified and more prospective data are required.