The collagen growth effects in rats using B. mori fibroin sponge sheet, pure fibroin solution and chitosan sponge sheet were investigated. Histopathological inspection of the wound 12 days later showed the increse of a vascular ingrowth and the absence of inflammatory cells. Wound healing effects were accelerated in the order of Fibroin sponge sheet$geq$Fibroin dressing solution〉Chitosan sponge sheet〉Control. The mean percentage of collagen production in rats after 12 days was 46.12$pm$4.58% and 42.11$pm$5.67% in fibroin sponge sheet and dressing solution-treated rats, respectively. These values were higher than the relative content in the chitosan sponge sheet and control groups, which was 23.87$pm$3.24 and 2.42$pm$0.32%, respectively.