Abstract: Macerate 1.0g of the powdered sample with 20.0 ml of chloroform plus 0.3ml of 25% NH₄ OH in a glassstoppered flask overnight. Take exactly 10.0 ml of filtrate, evaporate and dissolve the residue in 1.0 ml of chloroform. Spot the resulted solution for thin layer chromatography on a layer of alumina (without binder) with xyleneacetone-absolute ethnol-diethylamine (50: 40: 10: 0.6) as the developing solvent, by which anisodamine, hyoscyamine, scopolamine, anisodine and cuscohygrine can be separated. Locate the alkaloid spots by spraying the layer with modified Dragendorff reagent-Wagner reagent (1: 1). Collect separately the coloured spots from the layer into a collector, for anisodamine elute with 10.0 ml of chloroform containing 4% acetic anhydride, for hyoscyamine and scopolamine, first moisten the alumina in the collector with two drops of conc. ammonium hydroxide, then elute with 10.0 ml of methyl alcohol. Collect the eiuates separately and evaporate to dryness on a boiling water bath (in case of anisodamine, evaporate acetic anhydride completely), to the residue add 2.0 ml of buffer solution of 0.04% bromocresol green (pH 5.6 for anisodamine and hyoscyamine, pH 4.5 for scopolamine), 6.0 ml of water, and 10.0 ml of chloroform, shake the mixture for three minutes. After separation of the layers, take exactly 6.0 ml of chloroform layer, add 1,0 mi of 0.006～0.01 N anhydrous alcoholic solution of potassium hydroxide, and calculate the results by comparison with standard curve prepared by the same procedure.The method is Simple and rapid, the results obtained are stable and reproducible, and can be used for various kinds of plant sample and preparations.