An HPLC undergraduate experiment on the analysis of traditional Chinese medicine (TCM) has been developed. Two commonly used herbs ("glycyrrhizae radix" and "cinnamomi ramulus") are studied. Glycyrrhizin, cinnamic acid, and cinnamaldehyde are chosen as markers for the herbs. The dried herbs in their natural state and a TCM preparation in powder form are analyzed. Gradient elution with diode-array detection is used for the separation and identification of the markers. Solid-phase extraction is employed for cleaning the sample solutions. (Contains 3 figures.)