Detailed chemical studies of the methanolic extract of Pseudopterogorgia elisabethae, collected from the Florida Keys, have resulted in the isolation of elisabethamine (1), a new diterpene alkaloid. Its structure was established with the aid of extensive spectroscopic studies. Compound 1 exhibited cytotoxicity against lung and prostate cancer cell lines as determined by an MITT assay. (C) 2000 Elsevier Science Ltd. All rights reserved.