Background: Capsule formation around breast implants, development of tendon adhesions after tendon repair, intestinal brits after laparatomies, hypertrophic scars in skin incisions all are the results of excessive collagen synthesis to the extracellular matrix by fibroblasts. Any intervention that leads to cessation of collagen synthesis in these clinical situations may help to prevent these untoward results of wound healing. Although 5-fluorouracil (5-FU) is used mainly as a cytotoxic drug in chemotherapy protocols, it decreases cellular metabolism and blocks protein synthesis only at lower concentrations. Findings have shown that 5-FU downregulates fibroblast proliferation and differentiation in vitro. It has been used to treat fibroproliferative disorders of the eye and skin and is thought to inhibit thymidylate synthetase, blocking DNA replication.