Abstract:The root of Bupleurum chinanse and B. scorzonerifolium was examined histochemically in order to clarify the distribution of saikosaponins in various tissues and parts of the root. By means of qualitative and quantitative analyses, saikosaponins, the bioactive principles in the root, were found to be abundant in the cortex outside the cambium and very little in the xylem of the root. It was also found that the thinner root hairs had the highest contents of saikosaponins, but decreased towards the thicker root head.