Dear Cecil: There is a common (I hesitate to say "popular") salt substitute called NoSalt that consists of the compound potassium chloride (which is indeed a salt, but not a sodium-based one). This compound is used in other salt substitutes as well. Curiously, this very same compound has been used on several occasions by Dr. Jack Kevorkian for euthanasia (including, if I am not mistaken, his most recent, televised one) and also in executions. It works by stopping the heart. Admittedly this is a sensitive question — we don't want to give anyone ideas — but I cannot resist the natural query: how much NoSalt would one have to consume (orally) to experience cardiac arrest? The makers of NoSalt do not volunteer this information on the package. And why did Kevorkian resort to carbon monoxide when he lost his license and could no longer procure drugs, when presumably all he'd need to do was go to the grocery store, buy some NoSalt, mix it in some water, and inject it (or maybe just fix a large quantity of NoSalted pretzels)? Eric Ewanco, Framingham, Massachusetts

Cecil replies:

Very funny, Eric. Then I pulled out a few reports of deaths and near misses involving potassium chloride and did some math. You know what? This is no joke.

Some cases from the medical journals:

An infant went into cardiac arrest after being fed a mixture of grits and salt substitute by his five-year-old sibling. He was revived and eventually recovered. Amount of salt substitute in the grits (not all of which were consumed): less than a tablespoon.

A 75-year-old woman with a bad heart began using Morton Lite Salt, a mixture of potassium chloride and ordinary salt (sodium chloride), on the advice of her daughter. Within a few weeks she experienced shortness of breath and swollen ankles. Eventually she was taken to the emergency room and treated for congestive heart failure.

A woman attempted suicide by swallowing 100 potassium chloride tablets. She went into a coma and despite treatment died after two weeks. Total consumption of potassium chloride: 60 grams. Equivalent in commercial salt substitute, assuming a typical mixture of 90 percent potassium chloride: 11 teaspoons.

Another woman taking potassium chloride tablets for a medical condition began using them whenever she felt weak or tired. One evening she began suffering from diarrhea. She was told to stop taking the pills but was found dead the next morning. An autopsy revealed she’d consumed 47 tablets.

A mother, following the instructions in Adelle Davis’s book Let’s Have Healthy Children (1972), fed her infant about three-quarters of a teaspoon of potassium chloride mixed with her breast milk. The child stopped breathing and though rushed to the hospital died after 28 hours.

Conclusion: You don’t have to swallow a whole lot of potassium chloride, as a salt substitute or otherwise, to have big-time problems.

That said, reports of deaths or close calls due to ingesting potassium chloride are rare. Children and people with medical problems are most at risk. The NoSalt label includes the warning “Persons having diabetes, heart or kidney disease, or persons receiving medical treatment should consult a physician before using a salt alternative or substitute.” But the label also says, “Recommended for salt or sodium-restricted diets … dietary reduction of sodium may help in reducing high blood pressure.” It goes on to offer a “suggested lifestyle modification for management of high blood pressure,” which to me suggests that consumers are being urged to self-medicate. The label on Morton Salt Substitute is clearer: “Consult physician before using any salt substitute.” However they label it, the fact that you can buy this stuff in the spice section of the supermarket has to give you pause.

As for Dr. Kevorkian, potassium chloride was only one of several drugs administered by his “suicide machine.” He also used a sedative and a muscle relaxant to calm the patient, neither of which was available at Safeway. Presumably he switched to carbon monoxide to avoid the spectacle of an unsedated, twitching death.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.