Abstract: The aqueous extract of Rhododendron thymifolium Maxim is a new medicine for chronic bronchitis patients in clinical therapy by oral administration. It was proved to be most satisfactory curative effect. Six substances are isolated from this plant and identified to be raffinose, scopoletin; fraxetin, hyperin, isohyperin and quercetin respectively by means of mp, paper chromatography, UV, IR NMR and MS. The raffinose and fraxetin are first discovered in Chinese rosebay plants.