New minor benzo[c]phenanthridine-type alkaloids, 12-hydroxycorynoline (I), C21H21-O6N, mp 245–246.5°, [α]D 0°, and 11-epicorynoline (IX), C21H21O5N, mp 195.5–196.5°, [α]D 0°, along with 6-oxocorynoline (X), were isolated from Corydalis incisa Pers. (Papaveraceae). These structures were established by the spectroscopic studies and chemical correlations with the derivatives of corynoline. © 1975, The Pharmaceutical Society of Japan. All rights reserved.