Background: In 1891, William B. Coley injected streptococcal organisms into a patient with inoperable cancer. He thought that the infection he produced would have the side effect of shrinking the malignant tumor. Hypothesis: Surgical infection may improve host response. Methods: 55 urinary bladder cancer patients, with radical cystectomy and lymphadenectomy were studied. Blood samples were taken on day 0 and day 1, 3, 6, 9 and 14 after operation and at 5-year follow up. TNFα, soluble TNFα receptor I and IL-6 levels in sera were determined by HS ELISA and/or ELISA kits. Plasma cortisol values were measured by RIA kits. Results: From 55 patients.27 infected (wound and urine infections) in 30 days after surgery, 5 patients suffered peritonitis 2 died following leakage of small intestine suture.23 uneventfuly healed.All patients were bacterially contaminated, as wound samples taken at the end of operation demonstrated. 21 died due to the metastatic cancer during follow up.On day 0 the circulating values of TNFα were lower in infected patients. TNFα started to increase from day 3 till day 9 never reaching values of uneventful healing group.Soluble TNFα receptor I was elevated in septic group while, IL-6 elevated on day 1 than decreased for 14 days. Cortisol concentrations were elevated on day 0 and a correlation was found between cortisol and TNFα. Number of serum lymphocyte reduced by half one day after operation. Recovery in 5 days resulted in uneventful healing in 10 days septic consequences. If no recovery death occurs. Conclusions: Measuring serum TNFα levels before and after operations can predict the outcome. The infection may improve host response. However, the postoperative infection is a double edge sword can result in a severe sepsis and/or can elevate immune response improving the outcome from operation and/or from tumor disease.