Abstract: Nine adsorbents and 139 solvent systems were studied for the adsorption thin layer chromatographic separation of digitalis glycosides, but only partial separation was ob- tained. Better results were observed with partition thin layer chromatography. The glass plate (18×5cm) was coated with a slurry of 1.3 g kieselguhr, 0.2 g gypsum, and 6.3 ml water, dried for 1 hr at room temperature and 1 hr at 120℃.The plate was then developed with a solution of 1.5 g formamide in 10 ml acetone or sprayed with a 10% formamide solution in acetone, in such amount as to make each plate hold 0.8-0.9 g formamide. Suitable amount of glycoside dissolved in chloroform-methanol mixture (1:1) was applied to the plate, and the chromatogram was developed with a formamide-saturated solvent; when the solvent reached the top, the plate was taken out and heated for 20 min at 120℃ to remove formamide, then sprayed with 50% sulphuric acid immediately, the glycosides were seen as differently coloured spots. The following solvent systems gave the best separation: Chloroform-acetone-ethyl acetate-formamide (5:2:3: saturated) ; chloroform-acetone-ethyl acetate-ethanol-formamide (8:2:0.5: 0.5: saturated) ; chloroform-benzene-ethyl acetate-formamide (1:2: 3: saturated) ; chloroform-butylalcohol-formamide (9:1: saturated).