Abstract Five newalkaloids, dehydrocrebanine, 4,5-dioxodehydrocrebanine, stesakine, dehydrostesakine, bisaknadinine and four known alkaloids, lirodenine, lanuginosine, 1-tetrahydropalmatine, d-isocorydine with a few alkaloids of unknown structure were newly isolated fromStephania sasakii. The structures of the newalkaloids were determined from spectral data and chemical evidence.