Rhizoma Paridis total saponin (RPTS) had been identified as the major components responsible for the anti-tumor effects of the herb Rhizoma Paridis, which had been used in China for centuries to treat many diseases including tumor. To elucidate the anti-tumor mechanism of RPTS, a proteomic analysis was carried out with RPTS treatment in HepG2 cells. More than 50 proteins showed a significant change between control (0.01% DMSO) and RPTS (IC(50) approximately 10microg/ml) treated cells after 48h. Twelve proteins had been identified by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) using peptide fingerprinting from 15 protein spots (density difference >2 fold between the control and RPTS-treated group). Among them, six proteins were down-regulated (dUTPase, hnRNP K, GMP synthase, etc.) and six proteins were up-regulated (DNase gamma, Nucleoside diphosphate kinase A, Centrin-2, etc.) by RPTS treatment in HepG2 cells as determined by spot volume (p<0.05). Most of the identified proteins were associated with tumor initiation, promotion, and progression. These findings might offer valuable insights into the mechanism of anti-tumor effect affected by RPTS treatment in HepG2 cells.