High performance liquid chromatography (HPLC) analysis on the MeOH extract of Ligularia stenocephala leaves identified six caffeoylquinic acids, viz. 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoyl-mucoquinic acid, 3,5-di-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid, 5-O-caffeoylquinic acid, and 3-Ocaffeoylquinic acid using standard compounds, and determined the quantity of each extract. Percentage of total caffeoylquinic acids of the MeOH extract and its BuOH fraction were calculated as $67.83{pm}3.79%$ and $94.52{pm}1.84%$, respectively. Since the caffeoylquinic acid-rich MeOH extract exhibited a potent peroxynitrite-scavenging effect in vitro ($IC_{50}=0.87{pm}0.33;{mu}g/ml$ (mean $pm$ SEM)), the experiment was designed to identify whether or not that extract has an anti-obesity effect on rat obesity induced by high fat diet. Oral administration of the MeOH extract and its BuOH fraction abundant in caffeoylquinic acid decreased the rat body weight to the level of untreated group and decreased abdominal fat pad weight. The atherogenic index and thiobarbituric acid-reactive substance (TBARS) values were restored by treatment, indicating that the caffeoylquinic acid-rich extract probably inhibited hyperlipidemia and oxidative stress caused by high fat diet. These results suggest that L. stenocephala in vegetable form or its caffeoylquinic acid-rich fraction (BuOH fraction) as an agent can be used for treatment or prevention of obesity.