In the first part of this study, which was already published in this journal, tissue- and serum concentrations of Mezlocillin were compared one hour after a single dose of 2 g injected either intraarterially or intravenously in patients with ischemic lesions, due to PAOD or moist diabetic gangrene. In nearly all tissues of the minor perfused metatarsus and in the thigh, estimated as being physiologically perfused, there was an impressive trend to higher concentrations after i.a. injection. The concentrations in the thigh were higher than in the metatarsus after both, i.a. or i.v. injection. In this second part, tissue concentrations are compared three to four hours after the end of i.a. or i.v. injection of the same dose. After this interval of time, there is no longer any striking difference between the tissue concentrations after i.a. compared to i.v. injection within the physiologically perfused thigh, the concentrations in the reduced perfused metatarsus still show a convincing tendency to higher values after i.a. injection. It is concluded, that the initial tissue concentration of an antibiotic depends on its concentration within the inflowing blood and on the amount of the blood perfusion. The decline of the tissue concentration time course is more pronounced after i.a. injection. The advantage of higher concentrations after i.a. injection is limited to the initial phase after the injection.