Wound healing of injured skin and other tissues is fundamental for survival. Platelets are a rich source of potential wound-healing promoting factors. Four different human acute wound models and a wide array of clinical and laboratory wound healing assessment tools and parameters were to used to investigate the effect of an autologous platelet- rich fibrin; collagen synthesis and deposition in the ePTFE tube wound, breaking strength of small human incision wounds, epithelialization of the split-thickness skin graft donor site wound, epithelialization of the transplanted meshed autograft on a surgically revised leg ulcer, recovery of skin physiological properties over 1 year using non-invasive techniques (erythema, pigmentation, TEWL). The thesis is organized into an introduction to the wound healing process with emphasis on collagen metabolism and the very potent profibrotic growth factor TGF-b1, followed by a short literature review on the clinical use of different platelet-rich preparations. Specific studies are presented in detail, experimental methods are explained and results presented and discussed.