Abstract: (1)In the two species of Chinese rhubarb,Rheum palmatum L.and R. officinale Baill.,the content of combined rhein-like compound responsible for the purgative action of the rhubarb as reported by Fairbairn and Lou are presented. (2)The adsorption chromatograms of the two Chinese rhubarbs described above and a third so called Tu Ta-Huang are studied using a mixture of heavy magnesium carbonate and alumina(3:1)as adsorbent and 95% alcohol or chlo- roform as solvent. (3)Paper adsorption chromatograms are also given for three different species of Chinese rhubarb.The differentiation made between bhe three rhubarbs from these chromatograms could be used to identify them with satisfactory results.