Preclinical experiments with liposome-encapsulated anthracyclines indicate that this form of delivery may be effective in decreasing the cardiotoxic effect of these drugs. The tumor drug levels and the antitumor efficacy of anthracyclines in a number of mouse models are significantly enhanced by delivery in long-circulating liposomes. Drastic changes in the clinical pharmacokinetics of doxorubicin have been observed using liposomal delivery. Clinical trials with liposomal anthracycline preparations are ongoing to determine whether the pharmacokinetic changes are translated in a superior therapeutic index of this important group of chemotherapeutic agents.