Hepatocyte growth factor (HGF), originally implicated as a long-sought after hepatotrophic factor, supports epithelial branching duct formation in the developing lung as, a mesenchymal-derived morphogen. HGF elicits a potent organotrophic function for regeneration of organs including the liver, kidney and lung, through epithelial-stromal interactions. It prevents the onset or progress of hepatic fibrosis/cirrhosis, as well as the accompanying severe hepatic failure, and may become an effective drug for the treatment of fatty liver. HGF prevents the onset of acute and chronic renal failure, acts as pulmotrophic factor which enhances lung regeneration, and suppresses the onset of lung fibrosis. HGF may also be effective for treatment of vascular diseases, gastric ulcers, diabetes mellitus and neuronal diseases. Our results provide a new therapeutic strategy for treating such diseases.