Fugu by Gary Podolsky MD



Fugu Takifugu is a genus of pufferfish, often better known under the Japanese name Fugu (?? or ?).. Pufferfish defend themselves by inflating their bodies to several times normal size and by poisoning their predators. These defenses allow the fish to explore actively without much fear of being attacked.

The fish is highly toxic, but despite this or perhaps because of it it is considered a delicacy in Japan. Pufferfish contain lethal amounts of the poison tetrodotoxin in their internal organs, especially the liver and the ovaries, but also in the skin and the testicles. Therefore, only specially licensed Fugu chefs can prepare and sell fugu to the public, and the consumption of the liver and ovaries is forbidden because they contain the highest concentration of tetrodotoxin. However, because small amounts of the poison give a special desired sensation on the tongue, these parts are considered the most delicious by some gourmets. Every year a number of people die because someone has underestimated the amount of poison in the fish. Domestically in Canada Fugu is a rare delicacy but travelers may encounter Fugu preparations.

Fugu Intoxication/Poisoning

The poison paralyzes the muscles while the victim stays fully conscious, and eventually dies from respiratory failure. There is no antidote, and the standard medical approach is to try supportive therapy until the poison wears off. The fish is also featured prominently in Japanese art and culture. Fugu is also popular in Korean cuisine.

The fish's main lethal defense, is the neurotoxin contained in its internal visceral organs (the ovaries and the liver and to a lesser extent the intestines) and in the skin. Only minute amounts exist in the muscles and blood. This makes the fugu a lethal meal for most predators, including the occasional human.

The toxin- tetrodotoxin ( anhydrotetrodotoxin 4-epitetrodotoxin) is 1200 times deadlier than cyanide. The pufferfish does not create the poison itself. This poison is generated by the bacteria Pseudomonas and is also found in other marine animals such as the Blue-Ringed Octopus , and Cone Snails and also in some newts. These animals use the tetrodotoxin as a defence. Blue octopus bites and cone snail envenomations are medical emergancies as theyare frequently lethal.

The fish obtains the bacteria by eating food containing these bacteria. Pufferfish born and grown in captivity do not accumulate tetrodotoxin until they ingest the poison-producing bacteria, often by eating tissues from a toxin-producing fish. Also, some fish are more poisonous than others. Some fish may have enough poison to kill 30 adults.


Fugu has been consumed in Japan for a long time, although its historic origins are unclear.. Strict fishing regulations now protect fugu from being decimated.

Fugu prices rise in the fall and peak in winter, which is the best time to eat fugu, as they fatten to survive the cold. The fugu is shipped to the restaurant alive and stored in the restaurant in a large tank, usually prominently displayed. As fugu are aggressive and have sharp teeth, in captivity the mouths of fugu are often sewn shut to prevent the fish from injuring each other.

Since 1958, only specially licensed chefs have been allowed to prepare and sell fugu to the public. The fugu apprentice needs a 2-3 year apprenticeship before being allowed to take an official test. The test consists of a written test, a fish identification test, and a practical test of preparing fugu and then eating it. Only 30 percent of the applicants pass. The other 70 percent do not die from poisoning but fail from a small mistake in the long and complicated procedure of preparing the dish. Due to this rigorous examination process, it is considered safe to eat the sliced fugu sold in restaurants or markets.

A special knife called fugu hiki is traditionally used to slice fugu and it is usually stored carefully in a separate location from other knives.



In Winnipeg there are no registered Fugu Chefs. Given the very small market for Fugu and the need to keep it fresh make its unavailability a certainty in the near future. In the US some Fugu restaurants serve fish that do not contain any toxin.

Most fugu sold nowadays comes from fish with only a small amount of toxin. Selling or serving the most toxic liver is illegal in Japan, but this "forbidden fruit" is still sometimes eaten by amateur cooks, often with fatal results. After several homeless people died from eating fugu organs that had been discarded into an insecure trashcan, restaurants in Japan are now required to store the poisonous inner organs in specially locked barrels that are later burned as hazardous waste. Prepared fugu is also often available in grocery stores which must display official documents which license them to distribute fresh fugu.

While fugu connoisseurs love the taste and the texture of the fugu, many people actually find it rather bland and tasteless. Some professional chefs prepare the fish so that there is a minute amount of poison in the meat, giving a prickling feeling and numbness on the tongue and the lips.



Fugu poisoning

The tetrodotoxin is very stable and is not affected by the heat of cooking . It does not cross the blood-brain barrier which leaves the victim fully conscious while paralyzing the remainder of the body.

The first symptoms occur 15 minutes to several hours postingestion of tetrodotoxin containing fugu. In some cases this may occur up to 20 hours after ingestion. Initial symptoms include lip and tongue paresthesias, followed by facial and extremity paresthesias and numbness. Salivation, nausea, vomiting, and diarrhea with abdominal pain develop early.


Death can occur within 4-6 hours from respiratory muscle paralysis and respiratory failure. If the victim survives the first 24 hours, he or she usually recovers completely.

There is no known antidote and treatment consists of emptying the stomach, feeding the victim activated charcoal to bind the toxin and taking standard life-support measures to keep the victim alive until the effect of the poison has worn off.

Japanese toxicologists are currently working on developing an antidote to tetrodotoxin.

Commercially available fugu in supermarkets or restaurants is very safe and, while not unheard of, poisoning from these products are very rare. Most deaths from fugu occur when untrained people catch and prepare the fish, accidentally poisoning themselves. In some cases they even eat the highly poisonous liver on purpose as a delicacy. As not all fishes are equally poisonous so do not always lead to death, but small amounts of tetrodotxin give only the desired numbness on the lips and tongue during eating and shortly thereafter. However, in many cases this numbness of the lips is only the first step of a lethal fugu poisoning.

Some sources claim that about 100 people die each year from fugu poisoning, while others sources say only 10 to 20 per year, and still others state only 1 person dies each year from fugu.

According to the Fugu Research Institute, 50 percent of the victims were poisoned by eating the liver, 43 percent from eating the ovaries and 7 percent from eating the skin.

There are some reports of completely paralyzed but fully conscious victims that were believed to be dead, but woke up a few days later or just before being cremated. In some parts of Japan a fugu victim is put next to his coffin for three days to verify the death. If the body does not decompose, it is not yet dead.

Scientists at Nagasaki University have bred a non-toxic variety of. The non-toxic version is said to taste the same, but be completely safe for consumption.

Most Japanese cities have one or more fugu restaurants. They may be clustered together as past regulations had placed limits on where they may open their store and also the waterfront location of restaurants made it easier to have fugu delivered fresh.

Takefuku is a famous restaurant specializing in fugu in the Ginza district in Tokyo. Zuboraya is a popular Osakan restaurant chain. The people of Tokyo buy Takifugu rubripes at the Tsukiji fish market after the highly toxic liver has been removed. Few restaurants in the United States carry fugu and if it is available it does not contain any tetrodotoxin


Fugu and Travelers

Travelers to Japan and Korea may encounter Fugu restaurants, which are carefully regulated and very safe. The risk from eating fugu remains from ingesting fish not prepared by professionals. Any catches of puffer fish or other tetrodotoxin bearing species should never be eaten. Travelers to foreign countries merely need to be educated so that they do not eat amateur preparations of suspect catches.