Sucrose has been used to treat wounds with excellent results and with minimal abnormal scarring. In this study the effects of sucrose on collagen metabolism in fibroblast culture was evaluated. Sucrose (5.5, 15, or 25 mM) was added to granulation tissue, hypertrophic scar, and keloid fibroblast cultures, mRNA levels and procollagen aminopropeptides for type I and III collagens in cell culture medium were studied. Sucrose decreased mRNA levels for pro alpha 1(I) and pro alpha 1(III) collagens in fibroblast cultures derived from hypertrophic scar and keloid. In normal granulation tissue fibroblast cultures, 5.5 mM sucrose increased mRNA levels for pro alpha 1(I) and pro alpha 1(III) collagen, and higher concentrations decreased them. The synthesis of type I collagen decreased dose-dependently in all cell strains, whereas the synthesis of type III collagen decreased only in granulation tissue fibroblasts. To conclude, in vitro high concentrations of sucrose down-regulate both collagen gene expression and synthesis in normal granulation tissue fibroblasts, whereas in fibroblasts derived from abnormal scar sucrose down-regulates only type I collagen gene expression and synthesis, changing the pattern of collagen metabolism toward normal.