Ciguatera fish poisoning following consumption of a variety of fishes presents a distinct complex of polymorphous symptoms, including gastrointestinal (abdominal pain, diarrhea, vomiting, nausea), neurological (primarily parasthesia, dysesthesia), and cardiovascular (bradycardia, hypotension, tachycardia). The fishes involved include herbivores (surgeonfish) and carnivores (e.g., snapper, grouper, barracuda, jack, amberjack). Clinical symptoms seem to differ according to whether toxicity is caused by herbivores or carnivores, that is, there seem to be differences between the gastrointestinal and neurological symptoms associated with herbivores, and the gastrointestinal, neurological, and cardiovascular symptoms following consumption of carnivores. The final structure of ciguatoxin (CTX) from a carnivore species (moray eel livers) has been recognized as a lipid polyether closely related to other polyethers from dinoflagellates (okadaic acid, brevetoxin, maitotoxin, scaritoxin), to sponges (okadaic acid and norhalichondrin A), and to the streptomyces (antibiotics, monocarboxylic polyethers). Pharmacological studies suggest that, like the antibiotic polyether ionophores, ciguatoxin (Na + ) and its related polyethers likewise affect cell membrane and electrolyte imbalances. Screening of toxin fishes for ciguatoxin and related polyethers may soon be a reality employing monoclonal antibodies in the stick enzyme immunoassay. Research in human diagnostic tests and treatment of afflicted individuals is presently limited for ciguatera poisoning.