Two new alkaloids, corydalispirone, C20H17O6N, mp 196–198°, [α]d 0°, and cory-dalisol, C20H21O5N, mp 160–161°, [α]D +21.4°, were isolated from Corydalis incisa Pers. (papaveraceae). The structure of corydalispirone was established to be I by the spectro-scopic examinations and chemical correlation with bicucullinediol and adlumidinediol, and the structure of corydalisol was determined as VIII by the conversion to d-tetra-hydrocoptisine. Corydalispirone and corydalisol are noted as a new series of isoquinoline-type alka-loids having one more carbon atom at the benzyl moiety, and probably are metabolites of coptisine. © 1975, The Pharmaceutical Society of Japan. All rights reserved.