ABSTRACT
Marine animals secrete a wide variety of cardioactive substances which are of significance for man. Some toxins are part of a venom apparatus and the toxin is delivered by a bite or sting. In other cases, the toxin may accumulate in the food chain and produces toxic effects when the animal is eaten. In both situations, the toxin may represent a public health problem, and this may lead to its study. Some cardioactive compounds have also been discovered in programs searching for drugs from the sea. The compounds described are of considerable intrinsic interest. Many are of very high potency and may represent the most toxic compounds we know. Many have novel chemical structures.
