In 28 porcine partial thickness excisional wounds, the presence of several growth factors was first studied by enzyme-linked immunoadsorbent assay on wound fluid collected in sealed wound chambers. Basic fibroblast growth factor (bFGF) peaked on day 1 at 31.4 pg/ml; platelet derived growth factor (PDGF)-AB on day 3 reached 45.2 pg/ml, and transforming growth factor-beta (TGF-beta) on day 7 was 726.1 pg/ml. The same chamber system was used in 48 partial thickness excisional wounds for delivery of nanogram doses of bFGF, PDGF-AB, insulin-like growth factor (IGF)-1, epidermal growth factor (EGF), and cholera toxin. PDGF and EGF accelerated healing (1.1 days and 0.3 days, respectively), whereas bFGF and IGF-1 had no effect. Cholera toxin retarded healing by 1.9 days. Furthermore, in 100 excisional wounds EGF in the concentration range of 10 to 1,000 ng/ml had the same stimulating effect on healing. EGF at 10,000 ng/ml significantly delayed healing. The wound chamber model is useful for detecting of endogenous growth factors as well as for delivering exogenous factors.