The chapter on marine natural products with pharmacological properties covers molecules nominally produced by the organism from which they were first reported, with some overlap where it is now known that the actual producer is a microbe. Areas covered include toxins from Mollusca and Echinoderma, brominated compounds with antimicrobial activities, and antiviral compounds from Porifera including alkaloids and cyclic peptides, closing with a discussion of other pharmacological properties from marine invertebrates.