Objective To explore anti-tumor effect and mechanism of Allicin in treating murine bladder tumor.Methods: To observe Allicin’s effect on MBT-2 tumor cells in vitro

100 ⧎g/ml Allicin was added to the tumor cell culture

and the morphology of tumor cells was observed by phase contrast microscope 6 hrs later. The direct effects of Allicin on tumor cell growth in vitro in the MTT Assay was also evaluated. To determine anti-tumor effect of Allicin in vivo

C3H/He mice were randomly grouped prior to initiation of experiment. The mice received 1 × 105 MBT-2 cells administered subcutaneously into the right posterior flank on the Day 0 the experiment started. Allicin was injected at the site near tumor transplantation on the Day 1. The mice were examined for tumor development and the tumors were measured in two dimensions with calipers twice a week. On Day 21 the tumors were resected and examined pathologically to see the immune response.Results: The observation of morphology of MBT-2 cells in vitro and MTT assay indicated that Allicin has apparent direct cytotoxicity to bladder cancer cells. In high dosage group

a marked delay was shown in the appearance and growth of tumors after subcutaneously injection when compared with the control group (P< 0.01). Histology studies suggested that there were more macrophages

lymphocytes and fibroblasts at the peri-tumor region than the control group.Conclusion: Allicin has a marked tumor inhibitory effect on bladder tumor. This effect could possibly be related to direct cytotoxicity and activation of immune response. It could as possibly prove to be an effective intravesical treatment agent for superficial bladder cancer.