Mitomycin C is an antitumor antibiotic isolated from Streptomyces sp. Mitomycin is activated by reduction in vivo generating oxygen radicals which produce crosslinks in DNA by alkylaion. This mechanism ultimately inhibits DNA synthesis which has a bacteriostatic effect. Mitomycin C has strong antitumor activity, especially against Ehrlich ascites tumor cells, and strong bactericidal action against gram-positive and gram-negative bacteria.