This study compares the persistence and histological characteristics of gut suture with those of human amnion collagen, bovine collagen, and Vicryl suture implants in rats. Gut suture and human amnion collagen more resembled living tissue than did bovine collagen and were characterized by their cellularity and the presence of numerous capillaries. The Vicryl suture implants were quickly absorbed. Picrosirius polarization revealed the synthesis of host collagen by rat fibroblasts which immigrated into the gut suture and human amnion collagen implants. The authors suggest the potential of gut suture as a soft tissue substitute to improve linear skin contour deficits.