The structures of two new lycopodium alkaloids, serratine and serratanidine, which have been isolated from Lycopodium serratum Thunb. var. serratum f. serratum (=L. serratum Thunb var. Thunbergii Makino)4, 5) were studied. From the chemical and spectroscopic evidence, the structures of these alkaloids were established as serratine (VI) and serratanidine (VII), respectively. © 1968, The Pharmaceutical Society of Japan. All rights reserved.