Actinomycin C is an antibiotic complex composed of actinomycin C1, C2 and C3 and produced by Streptomyces chrysomallus. Actinomycin C reversibly binds to DNA, interfering with the synthesis of RNA, prevention of RNA polymerase elongation and, consequently, with protein synthesis. Actinomycin C exert an inhibitory effect on gram-positive and gram-negative bacteria and on some fungi. However, the toxic properties of the Actinomycin C in relation to antibacterial activity is such as to preclude its use as antibiotics in the treatment of infectious diseases. Because Actinomycin C is cytotoxic, it has an antineoplastic effect which has been demonstrated in experimental animals with various types of tumor implant. This cytotoxic action is the basis for its use in the treatment of certain types of cancer.