The formula for Coley toxins was the innovation of William B. Coley, MD, the attending bone surgeon from 1893 until 1936 at Memorial Hospital in New York City (now Memorial Sloan Kettering Cancer Center). Coley is credited with pioneering work in the field of immunotherapy based upon the work of earlier physicians in Germany. The physician’s interest in the subject developed when he lost his first cancer patient, a young girl with a sarcoma who died of metastatic cancer in spite of radical surgery. When Coley reviewed a hundred cases of sarcoma treated during the previous decade, he noted that patients who developed bacterial infections after surgery fared better than those who did not. For example, one patient with four instances of recurrent inoperable sarcoma of the neck had regressions of the sarcoma after infections with erysipelas (a superficial streptococcal infection of the skin)1,2.