AIM: To make isolation of a low polar fraction and its subfractions from Banlangen, dried root of Isatis tinctoria L , and study their immunocompetence. METHODS: A low polar fraction and its subfractions were isolated from Banlangen with dry column flash chromatography. It was tested that the effect of those fractions on chemiluminescence reaction of human polymorphonuclear cells. RESULTS: A two way immunocompetence was found from those fractions. The effect was activation while the concentrations of...