Checked content


Related subjects: Insects, Reptiles and Fish

About this schools Wikipedia selection

The articles in this Schools selection have been arranged by curriculum topic thanks to SOS Children volunteers. All children available for child sponsorship from SOS Children are looked after in a family home by the charity. Read more...

Fugu (河豚 : ふぐ) is the Japanese word for pufferfish and is also a Japanese dish prepared from the meat of pufferfish (normally species of Takifugu, Lagocephalus, or Sphoeroides) or porcupinefish of the genus Diodon. Because pufferfish is lethally poisonous if prepared incorrectly, fugu has become one of the most celebrated and notorious dishes in Japanese cuisine.


Fugu contains lethal amounts of the poison tetrodotoxin in the internal organs, especially the liver and ovaries, and also the skin. Therefore, only specially licensed chefs are allowed to prepare and sell fugu to the public, and the consumption of the liver and ovaries is forbidden. However, a number of people die every year from consuming improperly prepared fugu. The poison, a sodium channel blocker, paralyzes the muscles while the victim stays fully conscious, and eventually dies from asphyxiation. There is currently no antidote, and the standard medical approach is to try to support the respiratory and circulatory system until the effect of the poison wears off. It is alleged that non-lethal quantities of the poison remain in the flesh of the fish and give a special desired tingling sensation on the tongue, which leads to the fingers.

In 2008, advances in fugu research and farming has allowed some farmers to mass produce non-toxic fugu. Researchers surmised that fugu's tetrodotoxin came from eating other animals that had the tetrodotoxin bacteria, and developed immunity over time. Many farmers now are producing 'poison-free' fugu by keeping the fugu away from tetrodotoxin-laden bacteria. Utsuki, a town in Oita, became famous in selling non-poisonous fugu. No one has been poisoned eating it.


Takifugu rubripes for sale to master fugu chefs at the Tsukiji fish market in Tokyo– after the highly toxic liver has been removed.

Fugu has been consumed in Japan for centuries, although its historic origins are unclear. Bones of fugu have been found in several shell mounds called kaizuka in Jōmon period that date back more than 2,300 years. The Tokugawa shogunate ( 1603–1868) prohibited the consumption of fugu in Edo and its area of influence, yet it became common again as the power of the shogunate weakened. In Western regions of Japan, where the influence of the Government was weaker and fugu was easier to obtain, various cooking methods were developed to safely eat these fish. During the Meiji Era (18671912) fugu was again banned in many areas of Japan. Fugu is also the only delicacy officially forbidden to the Emperor of Japan, for his own safety.

The most prestigious edible species is the torafugu or Tiger Blowfish (T. rubripes), which is also the most poisonous. Other species are also eaten, as for example T. pardalis, T. vermicularis, and T. porphyreus. The Japanese Ministry of Health and Welfare has created a list which shows which species contain body parts that can be consumed. Other genera that can be consumed according to them include the puffers Lagocephalus and Sphoeroides, and the related porcupinefish of the genus Diodon.

Strict fishing regulations are now in place to protect the fugu population from being depleted. Most fugu are now harvested in the spring during the spawning season, and then farmed in floating cages in the Pacific Ocean. The largest wholesale market for fugu in Japan is in Shimonoseki.

Fugu prices rise in autumn 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 keep the fish from injuring each other. Prepared fugu is also often available in grocery stores, which must display official documents that license them to distribute fresh fugu. Whole fugu may not be sold to the general public.

Fugu in a tank

Since 1958, only specially licensed chefs can prepare and sell fugu to the public. The fugu apprentice needs a two- or three-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% of the applicants pass the test. This, of course, does not mean that 70% die from poisoning; rather they made a small mistake in the long and complicated procedure of preparing the dish. Due to this rigorous examination process, it is generally safe to eat the sliced fugu sold in restaurants or markets.

Furthermore, 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 the years following Japan's defeat in World War II, when several homeless people died from eating fugu organs that had been discarded into insecure trashcans, restaurants in Japan were required to store the poisonous inner organs in specially locked barrels that are later burned as hazardous waste.

A dish of fugu can cost easily ¥5,000 (approx. US$50) but it can be found for as little as ¥2,000 (approx. US$20), and a full course fugu meal can cost between ¥10,000 and ¥20,000 (approx. US$100 to US$200) or more. Due to the expense of fugu, the fish is sliced very carefully to obtain the largest possible amount of meat without the poison. 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.

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. The most popular dish is fugu sashimi, also called Fugu sashi or tessa, sliced so thin that the pattern of the plate can be seen through the meat. These plates are often decorated so that the removal of the slices will be aesthetically pleasing as well. The fins of the fish are also fried and served in hot sake, a dish called Fugu Hire-zake.

Vegetables and fugu can also be simmered as Fugu-chiri, also called techiri, in which case the very light taste of the fish is hard to detect among the taste of the vegetables and the dip. Fugu can also be eaten deep fried as Fugu Kara-age. If the spikes in the skin are pulled out, the skin can also be eaten as part of a salad called yubiki.

In several remote locations, complex pickling processes have been devised, which allow the poisonous parts of the fugu to be eaten. While the exact methods are kept secret, they involve long and heavy saturation in sake and salt for over three years.

Fugu poisoning

Tetrodotoxin is a very potent neurotoxin that shuts down electrical signaling in nerves by binding to the pores of sodium channel proteins in nerve cell membranes. Tetrodotoxin is not affected by the heat of cooking. It does not cross the blood–brain barrier, leaving the victim fully conscious while paralyzing the remainder of the body. In animal studies with mice, 8  μg tetrodotoxin per kg body weight killed 50% of the mice. The pufferfish itself is not susceptible to the poison due to a mutation in the protein sequence of the sodium channel pump on the cell membranes.

The symptoms from ingesting a lethal dose of tetrodotoxin may include dizziness, exhaustion, headache, nausea, or difficulty breathing. For 50% to 80% of the victims, death follows within four to 24 hours. The victim remains fully conscious throughout most of the ordeal, but cannot speak or move due to paralysis, and soon also cannot breathe and subsequently asphyxiates. 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 in several medical research centres are currently working on developing an antidote to tetrodotoxin.

As mentioned above, commercially available fugu in supermarkets or restaurants is very safe and, while not unheard of, poisoning from these products is 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 fish are equally poisonous this may not always lead to death, but sometimes give little more than the desired numbness on the lips and tongue while eating and shortly thereafter. However, in many cases this numbness of the lips is only the first step of a lethal fugu poisoning.

Statistics from the Tokyo Bureau of Social Welfare and Public Health indicate 20-44 incidents of fugu poisoning per year between 1996 and 2006 in all of Japan, leading to 34-64 hospitalizations and 0-6 deaths per year, for an average fatality rate of 6.8%. Of the 23 incidents recorded within Tokyo between 1993 and 2006, only one took place in a restaurant, while the others all involved fishermen eating their catch. Much higher figures have been reported for earlier years, and for example in 1958– the first year the preparation of fugu required a special license in Japan– 176 people died of fugu poisoning. According to the Fugu Research Institute 50% of the victims were poisoned by eating the liver, 43% from eating the ovaries and 7% from eating the skin. One of the most famous victims was the Kabuki actor and "living national treasure" Bandō Mitsugorō VIII who requested four servings of fugu liver and, in 1975, died after eating them. The fugu chef of the restaurant could not refuse the request from such a prestigious artist. Subsequently, the chef lost his license for breaking the law.

There are some reports of completely paralyzed but fully conscious victims that were believed to be dead, and 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 then it is not yet dead.

The pufferfish is also reported to be one of the main ingredients used in voodoo to turn people into zombies. According to ethnobotanist Wade Davis, the pufferfish is the key ingredient in the first step of creating a zombie, where the tetrodotoxin creates a death-like state. In the second step, hallucinogens are used to hold the person in a will-less zombie state. There was considerable skepticism to Davis's claims; he was widely accused of fraud, and there has been no final statement as to the veracity of his findings.

Scientists at Nagasaki University have reportedly succeeded in breeding a non-toxic variety of torafugu by restricting the fish's diet. With over 4,800 fish raised and found to be non-toxic, they are fairly certain that the fish's diet and digestive process are what actually produce the toxins that make it deadly. The non-toxic version is said to taste the same, but be completely safe for consumption. Some are skeptical, saying that the species of pufferfish play an important role (the fish could have all been of the same species which are all non-toxic), and that the toxicity has nothing to do with the pufferfish's diet.

Recent evidence has shown that tetrodotoxin is produced by certain bacteria– such as Pseudoalteromonas tetraodonis, certain species of Pseudomonas and Vibrio, as well as some others– and that these are the source of the toxin in pufferfish.

On August 23, 2007, a doctor in Thailand reported that unscrupulous fish sellers sold meat from the highly poisonous puffer fish disguised as salmon, which resulted in the deaths of fifteen people over the past three years. About 115 people were brought to different hospitals. Fugu was banned in Thailand five years prior.

Social aspects

Fugu and Japanese amberjack by Hiroshige (1832)

The popularity of fugu in Japan is an interesting phenomenon. Fugu is a very expensive fish, has some potentially lethal side effects, and is by most people considered to have a very weak taste (although many Japanese gourmets would disagree). The combination of these factors would normally give humans a low preference for its consumption. However, it seems one of the attractions of the low-flavored fish is the risk of potential death, regardless of how low that actual likelihood stands in a commercial restaurant. It can be assumed that the fish would be much less popular if it were not so poisonous.

The Japanese poet Yosa Buson ( 1716–1783) expressed some of this feeling in a famous senryu:

I cannot see her tonight.
I have to give her up
So I will eat fugu.

In the Kansai region the slang word teppo, (鉄砲) meaning rifle or gun, is used for the fish. This is a play of words on the verb ataru (当たる), which can mean either to be poisoned or to be shot. In Yamaguchi Prefecture, the pronunciation fuku is common instead of fugu. The former means good fortune whereas the latter is a homonym for disabled. The Tsukiji fish market fugu association holds a service each year at the height of the fugu season, releasing hundreds of caught fugu into the (rather polluted) Sumida River. A similar ceremony is also held at another large market in Shimonoseki.

A rakugo, or humorous short story, tells of three men that prepared a fugu stew but were unsure as to whether it was safe to eat. To test the stew, they gave some to a beggar. When it did not seem to do him any harm they ate the stew. Later, they met the beggar again and were delighted to see that he was still in good health. After that encounter, the beggar, who had in fact not eaten the stew but hidden it, knew that it was safe and he could eat it. The three men had been fooled by the wise beggar.

Chairman Kaga, the fictional eccentric and flamboyant host of the cooking show Iron Chef, was said to have died of fugu poisoning after the regular run of the series ended. The Chairman was killed off partly because the actor portraying him, Kaga Takeshi, had prior commitments that prevented him from reprising his role in an Iron Chef special.

Lanterns can be made from the bodies of preserved fugu. These are occasionally seen outside of fugu restaurants, as children's toys, as folk art or as souvenirs for tourists. Fugu skin may also be made into everyday objects like wallets or waterproof boxes.

There is a fugu museum in Osaka.


Most Japanese cities have one or more fugu restaurants. They may be clustered together, as past regulations had placed limits on where the stores may be opened, and the proximity of restaurants made it easier to have fugu delivered fresh. A famous restaurant specializing in fugu is Takefuku, in the Ginza district in Tokyo. Zuboraya is another popular chain in Osaka.

Fugu is also consumed in South Korea, where it is known as bok (복). It is very popular in port cities such as Busan and Incheon. It is prepared in a number of dishes such as soups or salads and also commands a very high price.

Few restaurants in the United States serve fugu; as of 2003, only seventeen restaurants were licensed to do so, of which twelve are in New York. The fugu is first cleaned of the most toxic parts in Japan and then is freeze-flown to the USA under licence, in purpose-built, clear, plastic containers. The fugu chefs for U.S. restaurants are trained under the same rigorous specifications as in Japan.

Sale of fish belonging to this genus is forbidden altogether in the European Union.

Scientific usage

Fugu rubripes is a commonly used genetic model organism, particularly useful to bioinformaticians. The Fugu genome is unusually small for an organism of its complexity, and contains very little in the way of ' junk DNA.' This compactness makes its genome sequence very useful for identifying conserved functional elements.

Retrieved from ""