Although they differ only slightly from each other, the various anthracyclines have their own metabolic pathways and pharmacokinetic parameters. Doxorubicin and daunorubicin have a similar reduced metabolite which reaches low plasma levels in the case of doxorubicin, but is predominant in the case of daunorubicin: daunorubicinol. Aglycones are only formed in large quantities from aclarubicin: aklavinone. The plasma decay of doxorubicin levels is triphasic, with successive half-lives of 5 min, 1 h and 30 h. Unchanged daunorubicin is eliminated more rapidly from plasma, but its metabolite is eliminated more slowly. New anthracyclines such as pirarubicin are characterized by a large volume of distribution, suggesting a higher tissue fixation. These pharmacokinetic data must be kept in mind for the design of new protocols which are aimed to dose fractionation or tumor targetting.