Previous studies in recent years suggest that garlic has anti-proliferative effects against various types of cancer. In this study, the authors investigated anti-cancer activities of Ly Son's garlic extract on HT-29 human colon cancer cells by using trypan blue and MTT assays. Results showed that Ly Son's garlic extract solution was significant inhibition of HT-29 cells replication in comparison to control group. At the time point of 24, 48, and 72 hours after treated with 5 mg/ml and 10 mg/ml of Ly Son's garlic extracts have been shown significant inhibition the HT-29 cell proliferation (p0.01). Additionally, at concentration of 10 mg/ml, the Ly Son's garlic extract was significant inhibition of the HT-29 cells replication in comparison to the cells treated with 0,05 ug/ml of vincristine at 48 and 72 hours following up (p0.05). This finding indicates anti-replication of Ly Son's garlic on HT-29 human colon cancer cells.