Manzamine A (1) known as a cytotoxin exhibited potent antimalarial activity with 40% recovery 60 days after single intraperitoneal (i.p.) injection against mice infected with the malaria parasite Plasmodium berghei. Pachastrisamine (6), a simple derivative of a sphingosine, isolated from a sponge, Pachastrissa sp. showed a high level of cytotoxicity. New sesquiterpene carbonimidic dichlorides and related aldehydes (812) have been isolated as cytotoxic constituents of the sponge Stylotella aurantium and shown to have moderate cytotoxicity. Cyclic undecapeptides, barangamides AD (1316), have been isolated from the sponge Theonella swinhoei. Their structures were established by spectroscopic analysis and chemical reaction.