Aclarubicin (aclacinomycin A) is an anthracycline and topoisomerase II inhibitor that has been clinically tested against haematologic and solid tumors. Aclarubicin stabilizes topoisomerase I cleavage. Aclarubicin accumulates efficiently in the mitochondria of living human cells and leads to mitochondrial dysfunction. Aclarubicin inhibits reverse transcriptase, endothelin converting enzyme and collagenase, and is active against HIV.