The mechanisms of the mRNA synthesis-promoting action of ginsenoside-Rb2, were investigated at the gene level. Rot analysis suggested that the previously reported increase in RNA polymerase activity as a result of administration of ginsenoside-Rb2 might be because of its effect on a specific gene. In this regard, albumin mRNA, which is expressed specifically in the liver, was assayed by northern blot hybridization using albumin cDNA in normal rats, diabetic control rats and diabetic rats given ginsenoside-Rb2. When the level of albumin mRNA in normal rats was set at 100, the level was reduced markedly to 32 in diabetic control rats. In contrast, in diabetic rats given ginsenoside-Rb2 the level was 0.54, significantly higher (69%) than that in diabetic rats given no ginsenoside-Rb2. In addition, poly(A)+RNA was purified from total RNA and subjected to hybridization, and poly(A)+RNA bands with different charges were measured by densitometry. The results of the measurement revealed changes dependent on the charge, and this was confirmed by autoradiography. We found no significant difference in the transcription activity of albumin mRNA, however, it showed only a tendency to increase. This suggests that ginsenoside-Rb2 has some effect on post-transcriptional regulation of the stability of mRNA itself. The results of Rot analysis suggest that ginsenoside-Rb2 affects a specific gene alone.