Bacterial Ghosts (BGs) are empty, non-living cell envelopes of Gram-negative bacteria. BGs are created by the controlled expression of cloned PhiX174 gene E introducing a distinct hole in the cell envelope of bacteria. Therapeutic application areas of the BG platform are manifold and include immunotherapy of cancer, human and veterinary vaccines, BGs as carrier and delivery system for drugs or other active substances. Bacterial Ghost Cancer Immunotherapy (BGCI) approaches comprise therapeutic in situ autovaccination defined as targeting and modulating properties and functions of the tumor microenvironment (TME) by BGs. Natural adjuvant and multi TLR-agonists properties of BGs do modulate the behavior and properties of immune cells present within the TME by switching the suppressive mode to immunostimulatory improving tumor antigen processing and presentation, and even eliciting long-lasting adaptive immune response against tumor antigens. Several tumor BG adjuvant studies investigating lung carcinoma, peritoneal carcinomatosis caused by colorectal or ovarian cancer derived from theallograft cell lines LLC1, CT26 and ID8, respectively, in immune competent mice provide evidence for activated cytotoxic anti-tumor T-cell responses and improved clearance of tumor burden. In combination with Oxaliplatin even complete remission of colorectal carcinomatosis and ant-tumor immunity in the murine model used was observed.