Pufferfish contains Tetrodotoxin, a deadly toxin, 1200 times more poisonous than cyanide. The poison in one pufferfish can be deadly to 30 humans. There is no known antidote to Tetrodotoxin. Fugu, another species of fish that contains the same toxin is eatable in some restaurants in Japan. Fugu is served in some restaurants strictly controlled by law in Japan and several other countries, and only chefs who have qualified after three or more years of rigorous training are allowed to prepare it.