Yanhuning is a semisynthetic preparation of andrographolide. The chemical name of yanhuning is monopotassium anhydroandro-grapholide disuccinate (DASK). The urine and feces samples containing DASK were extracted with chloroform. The chloroform solutions were spotted on silica gel plates (F254) and developed with chloro form-petroleum ether-ethanol-glacial acetic acid (6:3:0.5:0.5). After development the plate was placed on a Shimadzu dualwavelength TLC scanner CS-930. A zigzag scanning was then carried out for each spot developed at s=290nm andR=360nm under ultraviolet reflection. The DASK in each spot was tdus quantitated. The re suits obtained in present paper indicate that the method is sensitive

accurate and specific and it is applicable for quuntitative analysis of DASK in biological samples