Plants to 1 m tall, stout, puberulent throughout. Root fusiform. Stem erect, striate, hollow, branching, base clothed in fibrous remnant sheaths. Petals white, broad-obovate, base cuneate. Fruit oblong-ovoid, ca. 5 × 4 mm; dorsal and intermediate ribs raised, lateral ribs winged; vittae 2–3 in each furrow, 4–6 on commissure. Seed face plane. This species is used in Guizhou and Sichuan as a regional substitute, known as duan pian fang feng. From the roots of Ligusticum brachylobum, which is used as a substitute for traditional Chinese medicine Radix Peucedani in the southwest of China, 5 compounds were isolated and identified as umbelliferone, selinidin, anomalin, nodakenin and ferulic acid. 45 chemical components of the essential oil from Ligusticum brachylobum were identified. The constituents of the essential oil have been analysed by gas chromatography-mass spectrometry qualitatively and gas chromatography quantitatively. Forty-five compounds were identified.