Various phenotypic outcomes in mice following treatment with Salmonella. The inverse relationship between intrinsic therapeutic benefit and safety of bacteria mediated tumor therapy (BMTT) using Salmonella can be demonstrated through manifestation and progression of cancer and infection in mice. An inadequately attenuated, thus virulent, strain may successfully retard/regress tumor development albeit concurrently resulting in morbidity and mortality of the patient (strain A). Conversely, overattenuation may ensure patient safety at the cost of therapeutic efficacy (strain C). Intermediate levels of attenuation may yield corresponding levels of cancer progression and manifestation of infection (strain B). Thus, developing a properly balanced strain remains a challenge for successful therapy using Salmonella.