This chapter describes the chromatographic systems, such as sorbents and mobile phases used in the analysis of plant alkaloids and also the derivative techniques used to identify various compounds. Thin-layer chromatography (TLC) has been used since the 1960s to analyze and identify compounds in plants. Most TLC studies in plant chemistry have used silica gel as the sorbent, but studies on aluminium oxide and reversed phase plates are also available. The nonselective methods, which are used for organic compounds in TLC, such as quenching of UV light on fluorescent plates, iodine spray reagent, or iodine vapors and concentrated sulfuric acid, are often used. TLC of morphine, thebaine, codeine, and papaverine on silica gel with toluene–acetone–ethanol–ammonia as the mobile phase. Silica gel is used in numerous TLC studies of flavonoids. In addition to silica gel, polyamide is often used in the TLC of flavonoids and aglycones.