Adriamycin (ADR, doxorubicin), a drug having cardiotoxicity, is electrically charged as a cation in blood. We therefore investigated whether iontophoresis caused by direct electric current (DC; 50 microA, 90 min) would cause systemic modification of ADR pharmacokinetics. Cathode and anode were placed into a right kidney and muscles of the abdominal wall, respectively, in six Donryu rats. Urinary excretion of ADR, as measured by catheterizing into the right kidney, was significantly higher in the DC group than in the controls (p < 0.05). Both plasmic and renal ADR clearances were significantly higher in the DC group (p<0.005 and p<0.001, respectively). Tissue ADR concentrations were significantly lower in the DC group (heart: p<0.003; liver and lung: both p<0.05). These results suggest that electric therapy might potentially induce modification of ADR pharmacokinetics by iontophoresis, and that the therapy might effectively change ADR concentration both locally and systemically.