Five more peptide alkaloids have been isolated from the root bark of Ceanothus americanus L. Their structures were elucidated using the informations obtained from hydrolysis of the dihydro derivatives and from their mass spectrometric fragmentation reactions. Three of the alkaloids have been found to be identical with alkaloids known from other plants, Le., frangulanine (IV), adouktine-X (V), and adouktine-Y (VI). Two alkaloids represent compounds not described up to now, they have been named ceanothine-D (VII) and ceanothine-E (VIII).