Chemistry Learner

It's all about Chemistry

Home / Biochemistry / Tetrodotoxin


Though some animals of nature may seem very beautiful, but in reality they can be very dangerous. The animals have toxins which once injected may prove to be very lethal. Tetrodotoxin is one such poison found in various animals. Read on to know more about Tetrodotoxin.

Tetrodotoxin is a poison which is found in Puffer fish and several other animals such as blue-ringed octopus, harlequin frogs etc. It is a virulent poison which is considered to be 10 times more venomous than cyanide and is one of the most potent toxins present in nature. It is abbreviated as TTX and is also called Zombie powder by those who follow Vodou. Although the toxin is present in Puffer fish and the animals mentioned above, yet it is actually produced by a certain kind of symbiotic bacteria as well as some others which reside within these animals.


The first case of poisoning of Tetrodotoxin comes from the logs of Captain James Cook in 1774 who observed his crew eating puffer fish and feeding the remains to pigs. Soon after, the crew began to feel numbness and respiratory difficulties while the pigs died the very next morning. The name of the toxin was given in 1909 by Dr Yoshizumi Tahara, a scientist from Japan.


The molecule comprises of a +vely charged Guanidinium group which is made up of three atoms of nitrogen and a Pyrimidine ring along with additional fused ring systems.

Photos Of Tetrodotoxin
Picture 1 – Tetrodotoxin
Source –


The organ of Puffer fish contains certain amount of Tetrodotoxin which can very well paralyze the diaphragm and result in death because of respiratory breakdown. The toxicity, however depends on species, seasons, geographical locations etc. The near lethal doses of the toxin can leave an individual in a state of near death for several days.

Lethal Dose

According to the material safety data sheet the oral median lethal dose for an animal (mice) is 334 μg per kg while a single milligram or sometimes even less of TTX is enough to kill an adult human being.

Symptoms And Effects

There are several symptoms and effects of Tetrodotoxin. After a person eats a poisonous Puffer fish, the first symptom is a bit of numbness felt on the lips and tongue within 20 minutes to 3 hours. It is followed by escalating paresthesia in the face and extremities which may be followed by some feelings of lightness. The effects are in form of headache, diarrhea, epigastria pain and vomiting. Sometimes the person can feel difficulty to walk. The second stage is increasing paralysis where the victim is unable to move and experience difficulty in breathing. Speech too is affected and the victim exhibits signs of dyspnea, hypotension and cyanosis. Within 4 to 6 hours the victim dies.

Mode Of Action

Tetrodotoxin blocks sodium ion channel whose flow is very important for conduction of nerve impulses in excitable nerve fibers and along axon. Since Tetrodotoxin is larger than sodium it blocks its flow. The toxin affects the central nervous system to prevent the dissemination of nerve impulses.

Pics Of Tetrodotoxin

Picture 2 – Tetrodotoxin
Source –


No antidote for the poison has been developed. Due to this, cure of tetrodotoxin has to be carried out in natural ways. It is important to make the person vomit and empty his stomach. One can also feed the victim activated charcoal to unite the poison and take standard life support measures to keep the victim alive until the effects of the poison are gone. One also can inject a person with intravenous fluids along with alpha adrenergic agonists to fight hypotension.


The toxin is extensively used in the research of sodium ion channels. Since it specifically binds the sodium channel it provides more information regarding the secondary and the tertiary structure and nature of the channels. Research is being carried out as to whether the toxin can be used as an anesthetic or not.


The toxin is  insoluble in organic solvents where as solubility is limited in ethanol and ether. However, it is soluble in sulfuric and dilute acetic acid.

Medical Use

There are some medical uses of the toxin too. Tetrodotoxin has proved handy in the treatment of intense pain, cardiac arrhythmias, terminal cancers, migraines etc.

As aforesaid, this toxin can be found in many animals that are consumed by humans. It is better to avoid delicacies prepared from such animals or limit their intake to a minimum for safekeeping of your health.



Leave a Reply

Your email address will not be published.