Ciguatera fish poisoning, found throughout the world in warm waters, is the most common type of marine biotoxin ingestion. A polymorphous disease caused by toxins produced by coral reef dinoflagellate(s) and which concentrate up the food chain, ciguatera poses important health, nutritional, economic, and social problems for inhabitants of endemic areas. Despite considerable recent study and progress, the ecology and pathophysiology of the disease remain relatively little understood. Areas in which progress has been made include identification of the causative organisms and toxins and, to a lesser extent, treatment of affected persons. It has become clear that a variety of disturbances of the ecology of coral reefs may be associated with outbreaks of ciguatera. This paper reviews broadly the current knowledge of ciguatera, particularly the ecological, clinical, and socioeconomic aspects.