Cancer is one of the leading causes of death at present time. Millions of people die or have decreased quality of life every year around the world. Loss of labor because of cancer is also an important concern. In curable cancer types, the economic sources of the country are expended for drugs and medical materials. The scientists who are in search for the cure of cancer have used microorganisms and their products in their studies. In this article, the administration of bacteria and their products in cancer treatment is reviewed.