The success in therapy of prostaglandin E1 intra-arterially and intravenously applied to diabetics and non-diabetics with PAOD, stages IIb-IV according to Fontaine, was scrutinized in a city hospital primarily concerned with geriatrics, metabolism, and angiology. All the patients included were examined in retrospective studies with regard to the improvement of their situations during their stays in hospital and--in addition to that--a part of them prospectively some time after their stays in hospital. In all, 99 patients were included in the retrospective examination of which there were 60 diabetics and 39 non-diabetics. Of the 60 diabetics 53 were in stage IV, 5 in stage III, and 2 in stage IIb while in case of non-diabetics 26 were in stage IV, 10 in stage III, and 3 in stage IIb. 50 of the diabetics and 27 of the non-diabetics were treated intra-arterially. The prospectively orientated post-observation included 38 diabetics and 24 non-diabetics. The results of the retrospective examination revealed a significantly superior efficiency of intra-arterially applied PGE1 compared with the intravenous application, both, with regard to the reduction of needed analgesics and the improvement of the clinical situation. A comparison between intra-arterially treated diabetics and non-diabetics showed a significantly higher rate of success of the diabetics regarding to the improvement of the clinical situation. Concerning the prospective post-examination: due to their PAOD the diabetics took significantly more often analgesics at the time of their post-examination than the non-diabetics. Also concerning the development of their clinical situations the diabetics turned out to have worse results than the non-diabetics, however, the differences were not significant in this case.