A recombinant human fibroblast growth factor-20 (rhFGF-20) protein with pro-proliferative activity. Velafermin stimulates DNA synthesis and cell proliferation, specifically promoting epithelial and mesenchymal cell proliferation, and may prevent radiation or chemotherapy-induced oral mucositis. OR A substance that is being studied in the prevention and treatment of oral mucositis (sores in the mouth) in patients receiving high-dose chemotherapy. Velafermin belongs to the family of drugs called recombinant human fibroblast growth factors (rhFGF).