Eight alkaloids have been isolated from Corydalis ochroleuca Koch. Of these, six, namely, protopine, ochrobirine, l-tetrahydro-palmatine, bicuculline, l-corypalmine, and l-isocorypalmine, have been described from other sources. The last was the most abundant of the alkaloids in this plant, and was isolated in 0.11% yield of the dry weight. Two apparently new alkaloids have also been found. They are referred to as alkaloid F45 (C20H19O8N) and alkaloid F46[Formula: see text]. The former is phenolic and the latter contains a methylenedioxy group.