Abstract: A method of separation and quantitative determination of three coumarins, i.e. cichoriin, esculetin and prionanthoside, in the Chinese traditional drug Zihua Diding, Herba Violae, by high performance liquid chromatography is developed. The results showed that among nine Viola species, only Viola prionantha Bge, V mandshurica W. Beck.and V alisoviana Kiss; contain the coumarins, the content is highest in V prionantha. These effectivc compounds exist chiefly in the aerial parts of this plant and the content varied with the growth period. June is the best time for collecting Viola prionantha.

Key words: Zihua Diding, Viloa prionantha, High Performance Liquid Chromatography(HPLC), Cichbriin, Esculetin, Prionanthoside