Objective　 To investigate the effects of Xuezhikang capsule on the THP-1 macrophage-derived foam cell formation and the cholesterol efflux mediated by ATP binding cassette transporter A1 (ABCA1) and ATP binding cassette transporter G1 (ABCG1). Methods　THP-1 macrophages were induced to differentiate into macrophage-derived foam cells, and then they were divided into four groups: blank control group, ox-LDL group, Xuezhikang-treatment group, and vehicle group. The cells in four groups were co-incubated in culture medium, with addition of ox-LDL (100μg/ml), Xuezhikang (100mg/L ox- LDL+100μg/ml Xuezhikang) and vehicle solution (100mg/L ox-LDL+100μg/ml DMSO) respectively for 48 hours. The foam cells formation was observed with oil O staining. The contents of intracellular cholesterol and cholesterol ester in foam cells were determined. The mRNA and protein expression levels of ABCA1 and ABCG1 were determined by qRT-PCR and Western blotting, respectively. In addition, the cholesterol efflux was determined by liquid scintillation. Results　After co-incubation with ox-LDL, abundant lipid droplets were found in THP-1 macrophages, which was consistent with the morphological feature of foam cells. Compared with 3 other groups, the foam cell formation was attenuated by the administration of Xuezhikang. Compared with blank control group and vehicle group, the cellular lipid contents in Xuezhikang group significantly decreased (P<0.01), while the ABCA1 and ABCG1 expression significantly elevated (P<0.05), and the cholesterol efflux significantly promoted by Xuezhikang treatment (P<0.05). Conclusions　Xuezhikang may inhibit the foam cell formation in vitro by means of reducing intracellular cholesterol level. The cholesterol efflux is enhanced by Xuezhikang, possibly due to up-regulated expression of ABCA1 and ABCG1 in both mRNA and protein level. DOI: 10.11855/j.issn.0577-7402.2014.02.07