OBJECTIVETo investigate the inhibitory mechanism of Yiqijiedu granule on the implanted-tumor growth of nasopharyngeal carcinoma in nude mice.METHODSTwenty nude mice were injected nasopharyngeal carcinoma cells (HNE1), with 5 x 10(6) cells for a nude mouse. Implanted-tumors grew for 20 d, whose volume reached 1 cm x 1 cm x 1 cm. These nude mice were divided into 2 groups: Yiqijiedu group and control group. The Yiqijiedu group was given Yiqijiedu granule, and the control was given normal saline for 30 d, and then were killed. The volume and weight of implanted-tumors were measured. A 100-mg tissue from implanted-tumors was used to extract total protein by current methods, in which the proteins were separated by two-dimension electrophoresis and stained by silver, and protein profiles of implanted-tumors were obtained. Different proteins in the profiles were analyzed by ImageMaster 2D Elite 4.01. Nineteen different proteins, in which 4 expressed in the Yiqijiedu group, 4 expressed in the control, and the other 11 were differently expressed at 5 folds, were identified by MALDI-TOF-MS.RESULTSThe Yiqijiedu granule could inhibit the growth of implanted-tumors. The volume and weight of implanted-tumors in the Yiqijiedu group were (0.207 +/- 0.023) cm3 and (0.132 +/- 0.021) g respectively, and that of the control was (1.342 +/- 0.298) cm3 and (1.017 +/- 0.015) g ( P < 0.05). The inhibitory rate was 84.58%. The analyses of two-dimension electrophoresis and ImageMaster 2D Elite 4.01 showed that there were 567 +/- 49 protein dots in the Yiqijiedu group and 679 +/- 59 in the control. We found 243 proteins were dys-regulated, of which 112 proteins were observed, up-regulated and the other 131 proteins were down-regulated. MALDI-TOF-MS and Database analysis showed that the high expression proteins were HKR2 protein, 10 Phosphoribosyl pyrophosphate synthetase, TNFR superfamily member, and Apoptosis regulator. The lower expression proteins were Fibulin-3, Zinc finger protein 266, Carboxy terminus of HSP70-interacting protein, et al.CONCLUSIONYiqijiedu granule could inhibit the growth of nasopharyngeal carcinoma, which may be associated with those proteins regulated by itself.