Objective       To determine the inhibitory effect of garcinia acid combined with sunitinib on the growth of renal carcinoma cells.       Methods        Garcinia acid alone (0 to 8 μmol/L) or in combination with sunitinib (0 to 8 μmol/L) were used to treat 786-0 cells. MTT assay and flow cytometry  were used to detect changes in cell viability and cycle. Western blotting was used to detect the expression of proteins related to cell cycle and angiogenesis.  Xenograft model of 786-0 cells was constructed after treated by garcinia acid alone or in combination with sunitinib. Tumor growth and blood vessel growth in the nude mice were obser

ved and measured by immunohistochemical assay.       Results       The combination of garcinia acid and sunitinib  showed more significantly inhibitory effect on cell proliferation

and induced more cells arrested at sub-G

1

phase than monotherapy treatment (

P

0.05). Western blotting showed that the cell cycle regulatory protein Bcl-2 was significantly reduced

P21 expression was significantly increased

and VEGF expression was significantly decreased in combined treatment group than in the monotherapy group (

P

0.05). Xenograft growth and vascular formation were significantly inhibited in the combined treatment group than a single drug group in renal cell carcinoma transplanted nude mice（

P

0.05）.       Conclusion        The combination treatment of garcinia acid and sunitinib significantly inhibits kidney tumor formation than the individual drug alone.