This study was carried out to investigate the expression of various growth factors (GFs) involved in mucosal healing and thereby to clarify whether there are potential differences in the expression of GFs between normal colonic mucosa and the uninvolved mucosa of ulcerative colitis (UC). GF mRNA was investigated by reverse transcription polymerase chain reaction in colorectal biopsies from 20 normal controls and 15 UC patients. The positive rates (%) for mRNA expression for normal/UC were: epidermal growth factor (EGF) 65/53, transforming growth factor (TGF)-alpha 100/87, TGF-beta 1 60/33, insulin like growth factor-I 45/33, platelet-derived growth factor-A 55/67, basic fibroblast growth factor 0/0, hepatocyte growth factor (HGF) 50/53, EGF receptor 20/27, erb-B2 75/73, and HGF receptor (c-MET) 55/67. Semiquantitation of mRNA showed significantly lower expression of TGF-beta 1 (P < 0.05) in UC. Differences in expression and mRNA levels were not statistically significant for any other GFs. Our results indicate that mucosa in chronic persistent UC has a low basal expression of TGF-beta 1 mRNA, and, since TGF-beta 1 is a multifunctional GF that plays important roles in regulating repair and regeneration following tissue injury, this low expression may be partially responsible for the intractability of the disease.