Lanthanum salt is a prescription drug, but its underlying functions and mechanisms are not fully understood currently. To explore the potential therapeutic value of lanthanum chloride, cytotoxicity test was applied to investigate its effects on cell proliferation. Furthermore, we observed its influence on pro-oncogene c-met by reverse transcription polymerase chain reaction (RT-PCR). In MCF-7 cell line, lanthanum chloride repressed cell proliferation at high concentrations but had no significant inhibition effect on cell growth at low concentrations.However, we observed that lanthanum chloride repressed c-met transcription at a low concentration. This may suggest that lanthanum chloride is a potent drug to inhibit the high expression of c-met in carcinoma cells and play a clue for inhibiting the growth and invasion of tumor.