Why would you take poison as medicine?

Charles Alphonse Dufresnoy/

Humans have used poison to dispatch their enemies and rivals for a very long time. Some of history’s greatest figures met their ends through poisoning. For publicly criticizing the ruling class, the Greek philosopher Socrates was executed in 399 B.C. by being made to drink a cup filled with poison hemlock [source: Linder]. Hemlock depresses the central nervous system, leading to slowed respiration and pulse before the body shuts down [source: Perdue].

Around 3,000 B.C., the Kemite pharaoh Menes was documented as the first person to conduct research into poisons. Menes gave rise to a sophisticated knowledge of poisons among the Egyptians culminating 1,500 years later. A papyrus (ancient Egyptian document) dated circa 1553 B.C. found in Luxor, Egypt, in 1872 lists 700 different drugs (including poisons) of animal, mineral or plant origin [source: Hayes].

The Luxor papyrus also includes another significant source of ancient knowledge: antidotes to the poisons it listed. It’s a safe bet that about the same time humans came to understand poisons, they set about looking for antidotes to them. Some of these antidotes proved more effective than others. For example, whiskey was a standard treatment for snakebites in the 19th century. Experiments conducted by Brazilian researchers in the 1920s proved the method was worthless. Even worse, it actually hastened death by improving blood circulation and thus speeding delivery of the venom to the organs [source: New York Times].

­These same Brazilian doctors also came up with a clever method of fighting the effects of venom on humans by employing the same venom as an antidote -- using poison to fight poison. Researchers realized that by introducing gradually increased doses of snake venom into large animals like horses, the animal’s immune system would produce antibodies called antivenin that fight off the venom. Antivenin was extracted from the hemoglobin of an immunized horse’s blood, and, when introduced into the bloodstream of a snakebite victim, it attached to the venom and prevented it from interfering with normal body processes.

Other poisons have been shown to counteract the effects of poisons, and some are still being used in labs today. Find out more on the next page.

Poison as an Antidote

The venom of the Chilean Rose tarantula (shown at the San Francisco Zoo) contains a protein that can help stop heart attacks.
The venom of the Chilean Rose tarantula (shown at the San Francisco Zoo) contains a protein that can help stop heart attacks.
Justin Sullivan/Getty Images

A pretty full understanding of how the body works is required before one can confidently introduce poison into a human being as a means to cure illness. After all, just trying different poisons willy-nilly as antidotes ostensibly results in extensive deaths among a test subject population. Trial and error, in other words, isn't a good means of identifying which poisons can also serve as a cure.

This is why the use of poisons as antidotes didn't gain much traction until the 19th and 20th centuries. As physiological knowledge converged with scientific understanding of the poisonous properties of plants, the two were married to combat illness.

One of the first effective uses of a known poison as an antitoxin in modern medicine came in 1870, when Scottish physician Thomas Frasier used atropine as an acetylcholinesterase inhibitor [source: Heath]. Acetylcholinesterase is an enzyme that's naturally produced in the brain; it tells neurons to fire, which sends electrical impulses throughout the central nervous system. If it's not broken down, however, neurons will fire continually, leading to a nervous system overload and painful death [source: New Scientist]. Nerve toxins like sarin and anthrax inhibit the breakdown of this enzyme. The alkaloids found in atropine, which is derived from the poisonous plant known as deadly nightshade or belladonna, turns off the nerve receptors, counteracting the effects of these toxins.

It may sound like pretty dangerous toxicology (and it can be -- the alkaloid is deadly in high doses), but atropine is still used today as an antidote to nerve agents. And the line of reasoning behind using toxins as cures can be found in laboratories around the world in some radical treatments for disease. Instead of plants, however, a few researchers are looking to some of the most feared insects on Earth for cures.

Biophysicists from the University at Buffalo are using a protein from the venom of the Chilean Rose tarantula to combat death from heart attacks. The walls of your cells have tiny channels that open when the cell stretches. Among other body functions, these channels are responsible for the contraction of heart muscles. When these channels open too wide (which can happen from stretching the heart muscles over time), they allow a flood of positive ions into the cell. These extra ions disrupt the electrical signals in the heart, causing the organ to fibrillate (beat wildly and irregularly) [source: University at Buffalo].

The protein from the Chilean tarantula venom binds to these channels, which can block the positive ions from passing through. This could ostensibly prevent fibrillation -- and hopefully death -- if delivered during a heart attack [source: BBC].

The venom from another menacing arachnid is being used to help treat cancer. Researchers at the Transmolecular Corporation in Cambridge, Mass., have isolated a protein that occurs in the venom of the Israeli yellow scorpion. This protein has been shown to seek out and bind itself to the types of cancerous cells found in gliomas, a type of brain cancer that's particularly difficult to treat. The researchers created a synthetic version of the protein and attached radioactive iodine solution to it. When introduced into the bloodstream, the protein seeks out glioma cells and binds to them, carrying the radioactive solution along for the ride. The solution then destroys the cells -- and with enough treatments, the cancer [source: Health Physics Society].

With treatments like these emerging, perhaps the cure being worse than the disease isn't so bad after all.

For more information on poison and related topics, visit the next page.

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Sources

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  • Hayes, Andrew Wallace. "Principles and Methods of Toxicology, 4th Edition." CRC Press. 2001. http://books.google.com/books?id=dnjkZp2zP5AC&pg=PA5&lpg=PA5&dq=menes+egypt+poison&source=web&ots=HJe6RLDQ9i&sig=MrJmhqC3rgvIlYMnlTgH5WPIiRE&hl=en&sa=X&oi=book_result&resnum=4&ct=result#PPA5,M1
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  • "33 snakes robbed of venom; poison extracted from Bronx Zoo moccasins and copperheads to obtain serum; whiskey myth exploded; Brazilian scientists by tests on animals show alcohol aggravates the ill." New York Times. October 9, 1922. http://query.nytimes.com/mem/archivefree/pdf?_r=1&res=9E00E4DA1F30E433A2575AC0A9669D946395D6CF&oref=slogin