The aim of the present study is to develop microemulsion and liposome carrier systems for oral administration of transforming growth factor alpha (TGF-alpha) and to investigate the effects of these carrier systems on the gastrointestinal efficiency in rats. Microemulsion (w/o) and liposomes (MLV) were developed and characterised. The carrier systems were administered intragastrically by gastric cannula to male Wistar rats. The highest reduction in the basal acid secretion was observed in the microemulsion containing TGF-alpha and aprotinin group (TAME). The gastric mucus secretion in microemulsion containing TGF-alpha (TME) and TAME treatment groups increased significantly compared to the other groups. TGF-alpha levels in both stomach and duodenum were significantly increased in the TAME group. As a result, it was determined through confocal laser scanning microscope (CLSM) studies that exogenous-applied TGF-alpha attached to endogenous EGF receptors. The microemulsion formulation was found to be a more suitable carrier system for oral administration of TGF-alpha.