Abstract: The present disclosure relates generally to compositions, dosage forms, and methods for preventing and treating cancers and infections. An example method entails administering to the patient an effective amount of a composition comprising 1×107 to 500×107 intact, stabilized and substantially non-viable E. coli cells which have been treated in such a way as to result in about 70% to 99% reduction of lipopolysaccharide (LPS)-associated endotoxin activity when measured by the Limulus Amebocyte Lysate (LAL) assay as compared to untreated, wild-type E. coli cells, and wherein the composition contains 124 to 62000 endotoxin units (EU) of LPS.