A new alkaloid, named erythramine, has been isolated from the seeds of Erythrina sandwicensis Deg. and Erythrina subumbrans (Hassk.) Merrill. Hypaphorine was isolated anew from Erythrina sandwicensis and was re-isolated from Erythrina subumbrans. The crystalline erythramine base, hydriodide, hydrobromide, and the hydrochloride have been described. The microanalyses showed that erythramine has the empirical composition, C18H21NO3. Erythramine was strongly active in causing a curare-like paralysis in frogs. Hypaphorine was converted to methyl ct-dimethylamino-β-(3-indole)-propionate methiodide and this derivative was found to cause a curarelike paralysis in frogs when a high dose was administered. © 1939, American Chemical Society. All rights reserved.