Objective:To explore the effects of Rhein(RH) on proliferation and differentiation of human preadipocytes. Methods:Omental adipose tissue biopsies were obtained from 15 patients who were undergoing elective open-abdominal surgery. The primary culture and differentiation induction of human preadipocytes were performed, and the human preadipocytes were treated with rhein at different concentrations at proper moments. Dynamic morphological changes of the human preadipocytes were observed, and their proliferation and differentiation were assessed with Colorimetric MTT Assay and Oil Red O Staining. The expression of CHOP(a gene regulating the differentiation of preadipocytes) was detected by RT-PCR. Results:After 24 hours with RH, 2.5 ug/ml RH decreased the MTT values of the human preadipocytes by 35.5%(P < 0.05), compared with the control group without RH. The human preadipocytes with RH cumulated less adipose in the endochylema than those without RH obviously. 2.5 ug/ml RH decreased the differentiation degree of the human preadipocytes differentiated 8-10 days by 66.2%(P < 0.05). 1 ug/ml RH increased the mRNA level of CHOP obviously compared with the control group. Conclusion:Rhein may significantly inhibit the proliferation and differentiation of the human omental preadipocytes, which would contribute to the increased expression of CHOP gene.