Various tissues were excised from the gastropod mollusc Charonia sauliae and examined for tetrodotoxin (TTX) toxicity. In addition to the digestive gland (known to be toxic), the ovary also was toxic in some specimens, with the highest value being 199MU/g.Toxins were partially purified from both these tissues, and analyzed for composition by HPLC. The toxins from digestive gland were composed almost exclusively of TTX, whereas those from ovary featured the presence of appreciable amounts of anhydro TTX and 4-epi TTX, in addition to TTX. Toxins from two gastropods (frog shell Tutufa lissostoma and “araregai” Niotha clathrata) run for reference, contained another toxin, considered to be tetrodonic acid, as well.