Resistance to anti-cancer therapy in patients with advanced solid tumors reveals the need for new treatments.  Major challenges of Anti-cancer therapy is, specificity of treatment. Treatment will be ideal if cancer cells be eradicated without side effects on normal cell.

 Bacteria are used in different ways to treatment of cancer, either to provide direct tumoricidal effects or to deliver tumoricidal molecules .there are two ways to use bacteria as vectors, included, tumor-specific bacterial replication and  intracellular plasmid transfer. On the other hand, Bacterial toxins act by killing the cells and control of cellular processes for example cell proliferation, differentiation and apoptosis that they are associated with cancer. Spores are very resistant bacteria that survive even in oxygen-rich conditions, but, they are not able to grow. In conditions tumor the spore grow and germinate without affecting on normal cells. Bacteria and immune system: bacterial DNA vaccines apply immune system against cancer cells via cancer antigen Presentation. Here, we review the Different applications of bacterial therapy, mechanisms of action and successes at preclinical and clinical levels. Further developments in these studies will add a new dimension to cancer treatment.