Abstract:This paper deals with the quality control of the main active alkaloid principles in the crude drug, stem and leaf of Stephania tetrandra, by dual-wevelength TLC densitometric assay. The precision of the method is described. Results of recovery are satisfactory. The method has been applied to the analysis of various samples, including those from different parts of the plant. The procedure is simple, convenient and rapid and the results are stable and reproducible.