In this article,we investigated the thread and method of studying the antiviral effect substance of Traditional Chinese Medicine(TCM) against respirovirus,and Isatis indigotica Fort.,a widely used TCM in china, was taken as an example, antiviral effect constituents structure of substance of which was deeply researched. Isatis indigotica Fort. from different areas were collected,and HPLC method was used to determine the contents of antiviral constituents/components in them(epigoitrin, 2,4(1H,3H) -quinazoline...