Allicin is derived from Garlic. And has strong antibacterial properties; that would give reason for its use against cancer. It also has an oxidation effect on cells. Allicin taken by raw garlic is lost in after passing through the liver making in nonbioactive in organs and tissues.
Allicin extracts are quite unstable therefore it cannot be relied upon. The extract loses its beneficial properties within hours and turns into other sulfur containing compounds. It demonstrates antibacterial, anticancer and chemo preventive activities. Although in vitro it has good anticancer properties and benefits the biological activity of allicin is unstable, it is its instability that causes it to be an uncertain treatment for humans.