Ditiocarb, the sodium salt of diethyldithiocarbamate, is a drug with strong antioxidant capacity and chelating activities. It improves the depressed immune responses of newborn and aged mice and mice that are treated with chemotherapy or irradiation. Ditiocarb prevents cisplatin nephrotoxicity in animals without reducing the drug's antitumor activity. Ditiocarb has therapeutic activity in the LP-BM5 murine retrovirus-induced immunodeficiency disease. In that AIDS model, it reduces lymphadenopathy and hypergammaglobulinemia, restores immunocompetence, and prolongs survival. Ditiocarb was safe and reduced the incidence of opportunistic infections in patients with symptomatic HIV infection but ditiocarb had no positive effect on HIV patients. The administration of ditiocarb did not induce any major adverse clinical or biological reactions. Sixty-four patients with nonmetastatic high-risk breast cancer were randomized in a double-blind trial of adjuvant immunotherapy with sodium ditiocarb (DDC) versus placebo. At 6 years, overall survival was 81% in DDC group versus 55%.