1. The method of protected coagulum has withstood the test of time for three decades and, as confirmed by the literature, its principle has been in recent years increasingly applied in the form of single-dose perioperative administration of antibiotics. 2. The method has proved its value in vascular prosthesis as blood coagula are the source of morphogenesis of the vascular wall in prosthesis. 3. In 1 657 patients undergoing arterial reconstructive procedures the method reduced infection rate of 0.9%. 4. There is experimental evidence that, given in therapeutically active doses, tobramycin, lincomycin and cephazolin form protected coagula with prolonged antibiotic action.