3 Countermeasures against Radioactive Fallout

The information in this post comes from the U.S. Department of Health and Human Services (HHS) website: Radiation Emergency Medical Management. A radiation emergency might occur from a nuclear bomb, a dirty bomb, or a nuclear power plant disaster. The same site has a page of information on Managing Internal Contamination with radioactive compounds. Of particular interest, for prepping purposes, is a section of the page titled Radiation Countermeasures for Treatment of Internal Contamination. These counter measures include the use of cheap over-the-counter compounds which block radioactive elements from being absorbed by the body, or decrease the likelihood that they will be stored in the body (e.g. in the thyroid, bones, or teeth).

But there is also this warning page, Caveats about Radiation Countermeasures for Treatment of Internal Contamination, which states:

“Off-label use of medical countermeasures or use of non-FDA approved drugs to treat internal contamination carries an unknown risk-benefit ratio and warrants extreme caution.

“Except as indicated in the official package insert, there is very little information about using these medical countermeasures in infants and children.

“Decisions to use medical countermeasures to treat internal contamination should be made in conjunction with medical radiation or medical toxicology experts.”

You’ve been warned. Now on to the specifics.

Three Countermeasures

1. Potassium Iodide tablets (KI)

This one, you knew already. KI tablets block the thyroid from storing radioactive iodine, one of the most common radioactive isotopes in nuclear fallout. Essentially, you flood the body with non-radioactive iodine, from the KI tablets, and then any radioactive iodine is much less likely to be taken up and stored in the body. Radioactive iodine has a half-life of 8.1 days, and after 10 half-lives or 81 days, only traces of the radioactive iodine would be left. So it is a short-term countermeasure.

KIO3 tablets work in the same way. But KI is preferred, since KIO3 has a greater likelihood of causing intestinal irritation. According to the World Health Organization: “Tablets packed in a hermetic alufoil and kept in a dry and cool place preserve fully their iodine content for 5 years” [Guidelines for Iodine Prophylaxis following Nuclear Accidents, WHO/SDE/PHE/99.6]

2. Gaviscon

Gaviscon is an over-the-counter antacid. It contains aluminum hydroxide, which blocks the absorption, by your GI tract, of both radium and strontium, two radioactive compounds in nuclear fallout. The HHS site says: “Give one dose within 24 hr of radionuclide intake to block intestinal absorption; administer before absorption occurs.” So it is a one-time dose, to prevent absorption.

Aluminum hydroxide is also available, OTC, as a gel. But Gaviscon contains a second ingredient, sodium alginate (alginic acid), which the HHS site also lists as a blocking agent for radium and strontium. So Gaviscon is preferable.

What happens if radium or strontium gets into your body? Both strontium and radium will be mistaken by the body for calcium and deposited in the bones and teeth. That is not what you want. Strontium and radium remain radioactive for, well, the rest of your life.

3. TUMS (or generic calcium carbonate)

Gaviscon only blocks the absorption of radium and strontium. You need another countermeasure in case some of the radium or strontium is absorbed.

Since both of those radioactive elements are mistaken by the body for calcium, flooding the body with calcium makes it much less likely that the radium and strontium will be taken up and stored in the bones or teeth. The mechanism of action here is much the same as with the KI tablets. If you have enough calcium in your system from the TUMS (or generic calcium carbonate), then the strontium and radium are diluted and are less likely to be stored in the body. Your system takes up the ordinary calcium instead of the radioactive strontium or radium.

The HHS site says: “Use as directed on label” and “Begin therapy within 12 hr of radionuclide intake if possible”.

But while the aluminum hydroxide countermeasure (Gavison) is a one-time dose to prevent absorption, the Calcium Carbonate should be taken daily, during the time that exposure to the radioactive elements is likely.


The above 3 countermeasures are widely available, inexpensive, and are suggested by the HHS and other government authorities to treat internal contamination with radioactive elements. A nuclear power plant disaster is probably the most likely scenario. But we can’t rule out a terrorist dirty bomb, or a nuclear bomb from a rogue nation. In any case, it would be prudent to have the above countermeasures, stored in advance. Once an event occurs, people will buy up all the available OTC countermeasures.

Use Caution

Consult a physician before using any of the above countermeasures. Do not use when there is no radioactive fallout, as use of any of the above compounds is not without health risks.

More in my previous post: Antacids as a Treatment for Exposure to Nuclear Fallout

– Thoreau

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