Immunoaugmentative therapy is an unproved cancer treatment that until recently was offered to patients by zoologist Lawrence Burton, PhD, at a facility in Freeport, Bahamas. The therapy consists of serum measurements of certain "immune deficiencies" and purportedly restores immune function by injection of products variously derived from tumor tissue and blood from individuals with cancer and healthy volunteers. Immunoaugmentative therapy represents a potentially serious public health risk, since it is capable of transmitting hepatitis B and the presumed etiologic agent for the acquired immunodeficiency syndrome. Physicians and health officials who learn of patients receiving this therapy are advised that its efficacy remains unproved and that the risk of receiving contaminated blood products is considerable.