Hektoen International

A Journal of Medical Humanities

Fugu—Japanese delicacy or death?

In Japan, fugu has been a “captain of these men of death” for generations, causing an exitus that is “rapid and violent.” There is at first numbness around the mouth, then paralysis, and, as with curare, consciousness persists until the very end. The poison interferes with the transmission of signals from nerves to muscles by blocking the flow of sodium ions and the generation of electric potentials.

Fugu in Linnean parlance is a member of the family of Tetraodontidae fish, so named because their upper front teeth are fused to form plates they use to crush their prey. In English these fish are variously known as pufferfish, globefish, or blowfish. When threatened, they swallow enough water to double their size, converting their flat surface scales into dangerous spikes that protect them against their enemies. These unlovable creatures also contain in their entrails—liver, ovaries, intestines, eyes, and skin—a poison one thousand times more deadly than potassium cyanide and against which there is no antidote. Yet these fish are born as pure as the newborns in limbo, and only later accumulate the poison by being bottom feeders and ingesting the bacteria that produce it. Then like a treacherous Delilah, they seduce the credulous gourmet of sushi and sashimi with unfortunate results.

It was to avoid such catastrophes that several scientists, such as professors Juntaro Takahashi and Kichindo Inoko at the Tokyo Imperial University, tried in vain to isolate the toxin produced by these blowfish. But in 1884 Dr. Yoshizumi Tahara of the National Institute of Hygienic Sciences University began to investigate this subject and within five years achieved a breakthrough by using lead acetate precipitation to isolate the culprit poison. He named it tetrodotoxin, after the family of pufferfish from which it is derived, and it is customarily abridged to TTX. His methods paved the way for its large-scale extraction and purification.

Tahara’s discovery of TTX was a landmark achievement. It provided a clearer understanding of pufferfish poisoning and opened the doors for further research into the toxin’s properties and potential applications. TTX remains a subject of scientific interest because of its potential use in pain management. Tahara’s work has also contributed to the safe enjoyment of fugu, leading to the implementation of strict rules for its preparation by fugu chefs. These chefs require rigorous training for at least three years before being certified to serve what, at least in Japan, remains a popular and highly prized delicacy. By becoming expert in removing the toxic parts of the fish, they ensure that fugu continues to delight the palates of thousands of Japanese gourmets able to enjoy eating it safely.

Fugu in tank. Photo by Chris 73 on Wikimedia. CC BY-SA 3.0.
Takifugu rubripes on sale at the Tsukiji fish market in Tokyo, 2002. Photo by Chris 73 on Wikimedia. CC BY-SA 3.0.

GEORGE DUNEA, MD, Editor-in-Chief

Spring 2024



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