Dihydrochelerythrine is isolated and purified from the herbs of Chelidonium majus.Dihydrochelerythrine has antifungal activity against pathogenic plant fungi; it shows antiparasitic efficacy against Ichthyophthirius multifiliis in richadsin, it has potential application in the therapy of serious infection caused by I. multifiliis. Dihydrochelerythrine affects cell cycle distribution, activates mitochondrial apoptotic pathway, and induces apoptosis and necrosis in HL-60 cells.