This chapter presents the toxins and associated poisonings of pufferfish. It explores the many uses of pufferfish, such as in aquariums, for their nutritional and culinary value, and for their emerging uses in the treatment of pain. Arothron firmamentum is a poisonous species and is not to be eaten. Arothron hispidus is a component of the marine aquarium trade. It is also used as a cleaning fish in marine culture tanks and cages. Feroxodon multistriatus is a highly toxic fish and is responsible for amputation of swimmers toes. Takifugu pardalis is a poisonous species. Despite a ban on the sale of toxic pufferfish in fish markets, this species may sometimes be found in proc.essed fish products in Taiwan. Arothron carduus is a harmless species as its internal organs and skin are toxic; and muscle is less toxic. This species may be found in the curio trade, where it is dried and sold as ornamental product.