This study sought to establish a more reliable method of identifying the "monarch" or principal drug Radix inulae and its active component alantolactone (AL) in the Tibetan medicine Manuxitang. Radix inulae and AL in Manuxitang were effectively identified by thin layer chromatography (TLC). AL was quantitatively determined using gas chromatography in the range of 0.1-1.0 mug/mL (r = 0.9998). The precision was 1.20% (n = 6) with an average RSD of 1.74%. Recovery was in the range of 93.5-98.5% with RSD value of 1.85%. The methods established were simple, accurate, and specific and could be used for quality control of Manuxitang.