
In the last two decades a huge repertoire of research on the anticancer activity of organo sulfur compounds derived from Allium sativum (Garlic) has provided critical insight about the potential of garlic as a potent anticancer agent. Allyl sulfur compounds from garlic not only has been shown to be a chemotherapeutic compound but also, based on a number of in-vitro, in-vivo and case controlled population based studies, that it has a chemo preventive activity and showing inverse relation with the intake of garlic and incidence of cancer. Garlic has been shown to have inhibitory effect in different types of cancer that include carcinoma, sarcoma, myeloma and leukemia, having same molecular targets in the respective phase of regulatory and cell demise events, a feature highly desirous of current and future anticancer drug. Garlic has basically been shown to arrest cell cycle at the G2/M check point and induce apoptosis by cell cycle dependent or independent manner. This review contains the brief highlight of the chemistry of the organo sulfur compounds (OSC) from garlic that have anticancer property and detailed elucidation of the function of G2/M cell cycle checkpoint regulating molecules (Cyclin B1, Cdc25, Cdk 1, p53, Microtubule), apoptosis regulators infesting multiple signaling pathways that include cell survival pathway (Bcl-2, Bcl-xL, XIAP), mitochondrial pathways, and protein kinase pathway (JNK, Akt) and how these event regulators are modulated by the allyl sulfur compounds of the garlic culminating in the cell cycle arrest and apoptosis of the immortal cells.