Experimentally induced thrombi of ear veins in albino rabbits have been treated locally with heparin-containing ointments in presence or absence of allantoin and dexpanthenol, the heparin concentration varying. While the ointments, containing heparin only, induce no or only minor thrombolytic activity, the combination ointments Hepathrombin Adenylchemie containing heparin, allantoin and dexpanthenol show significant thrombolytic activity. This effect is dependent upon the heparin concentration, yet, heparin doses above 50 000 IU per 100 g of ointment do not enhance the thrombolysis furthermore. Further, the studies show that the effective components of Hepathrombin do penetrate into and through the skin, allantoin and dexpanthenol being important components of the ointment probably supporting the transdermal penetration of heparin. The studies also demonstrate the only local thrombolytic effect of the Hepathrombin ointments because the thrombus of the right ear, always treated with ointment base only, did not show any change in length as contrasted to that of the left ear of the same animal treated with the Hepathrombin ointments. Mechanisms of the locally by Hepathrombin/heparin induced thrombolysis will be discussed.