Three species of puffer fish, Takifugu poecilonotus, T. vermicularis and T. radiatus, were examined for the presence of toxic components other than tetrodotoxin. Saxitoxin, a paralytic shellfish toxin, was found in the livers, ovaries and digestive tracts of the first two species but not in the last species. The puffers are assumed to accumulate saxitoxin by feeding on bivalves that have ingested a toxic dinoflagellate Protogonyaulax tamarensis. Another toxic component is present in the liver of T. poecilonotus, but its structural relationship to tetrodotoxin or saxitoxin is questionable.