Aristolochia manshuriensis Kom., a climbing plant belonging to the Aristolochiaceae family, grows mainly in northeast of China. It has been used as a folk medicine in China for many years. As a diuretic and anti-inflammatory reagent, it was reported as Guanmutong in China pharmacopoeia in 1963 to cure edema and rheumatic pain [1]. The use of Guanmutong was banned in the mainland of China from 2003, mainly because of its nephrotoxicity caused by the aristolochic acids contained [2]. Pharmacological studies on aristolochic acids also revealed that they possess antitumor activity as well as enhance cytoimmunity and macrophagus function [3]. In order to find more bioactive compounds, the chemical constituents of this plant were investigated. Dried and powdered stems of Aristolochia manshuriensis Kom. (5 kg) were extracted three times with 95% ethanol under reflux. The solutions were combined and concentrated to yield a crude extract. The residue was suspended in water and extracted successively with petroleum ether, ethyl acetate, and n-butanol. The ethyl acetate extract (100 g) was subjected to silica gel column chromatography (CC) using gradient mixtures of chloroform–methanol (100:0–0:100) as eluants to afford 10 fractions (Fr. 1–10). Fraction 1 was separated on silica gel CC with chloroform–methanol (100:0–10:1) as eluants to afford 9 (50 mg). Fraction 2 was resubjected to silica gel CC with chloroform–methanol (100:0–10:1) as eluants to afford 7 (150 mg) and 8 (100 mg). Fraction 3 was purified by recrystallization to yield 1 (30 g), and the solution was subjected to silica gel CC using mixtures of chloroform–methanol (100:0–0:100) to afford 2 (15 mg), 3 (12 mg), and 6 (10 mg). Fraction 4 was subjected to silica gel CC eluting with chloroform–methanol gradient (100:0–5:1) to afford 3 (12 mg) and 6 (10 mg). Fraction 5 was purified by recrystallization to yield 10 (20 mg). Fraction 6 was subjected to silica gel CC using mixtures of chloroform–methanol (100:0–2:1) as eluants to afford 11 (15 mg). Their structures were identified to be aristolochic acid I (1) [4], aristolochic acid II (2) [4], aristolic acid I (3) [5], aristolochic acid Ia (4) [4], aristolochic acid IIa (5) [6], aristolic acid II (6) [4], p-hydroxycinnamic acid (7) [7], ferulic acid (8) [8], lignoceric acid (9) [9], vanillic acid (10) [10], and syringic acid (11) [11] on the basis of spectral data as well as by comparison with literature. Compounds 1, 2, 4–7, 10, and 11 were found before in this plant, and compounds 3, 8, and 9 were isolated from this plant for the first time.