1. The epigeal part of Thermopsis alterniflora at the beginning of flowering contains 3.35% of combined alkaloids. The separation of the combined bases yielded cytisine, N-methylcytisine, pachycarpine, thermopsine, and the new alkaloid alteramine. 2. The structure of 11-allyl-N-methylcytisine has been established for alteramine. © 1973 Consultants Bureau, a division of Plenum Publishing Corporation.