Fungal pathogens caused various diseases which resulted in heavy yield and quality losses on plants of commercial interests such as fruits, vegetables, and flowers. In our preliminary experimental results, the methanol extracts of four species of medicinal plants Melaphis chinensis, Eugenia caryophyllata, Polygonum cuspidatum, and Rheum officinale possessed antifungal activity to causal agent of cabbage anthracnose, Colletotrichum higginsianum. Thus it was conducted to identify and quantify the chemical constituents in these herbs and to assess the antifungal effects of these compounds. Among the tested principles, the indicator compound methyl gallate from M. chinensis was the most effective one against the conidial germination. In addition, it exhibited significant effects of controlling anthracnose disease of Chinese cabbage caused by C. higginsianum PA-01 in growth chamber. These results indicate that M. chinensis may be potential for further development of plant-derived pesticides for control of anthracnose of cabbage and other cruciferous crops.