The lotus seeds discovered from the prehistoric dwellings at Kemikawa in Chiba Prefecture in 1951, purported to be about 2000 years old, were sown and germinated. This ancient lotus has since been cultivated and was named "Ohga-hasu" to honor its finder and cultivator, Dr. I. Ohga. Scientific name given to this ancient lotus is Nelumbo nucifera GAERTN., the same as ordinary lotus. Examination of alkaloids in the leaves and leaf petioles of this lotus yielded the aporphine-type bases, roemerine (II), and nornuciferine (III), and benzyl-tetrahydro isoquinoline-type base, armepavine (IV), from the leaves, and roemerine (II) and nornuciferine (III) from the leaf petiole. Presence of nuciferine (I) in the leaves and petiole was presumed from the result of paper chromatography but was not isolated due to the small amount of the fresh leaves available. These results indicated that the alkaloids contained in this ancient lotus are the same as those in ordinary domestic lotus.