Every era has its essential consumer products—witness the ubiquity of cell phones and iPods today. In the first half of the 20th century, what gave some gifts their "gotta-have-it" allure is, in retrospect, rather alarming: radioactivity.

Naturally occurring "ionizing" radiation surrounds us, of course, whether it is welling up from the rocks beneath our feet or showering on us from space. But higher exposures to radioactive particles and energy can lead to illness, cancers and even death. Although radiation has proved immeasurably helpful in many applications, such as x-ray medical imaging, an understanding of its risks and how to safely harness its benefits took decades to acquire, and was not without incidents along the way.

"Some people jumped on the bandwagon, thinking [radioactivity] was the neatest thing since sliced bread," says Gary Mansfield, a retired radiation health expert who worked at Lawrence Livermore National Laboratory in California.

Marie and Pierre Curie's 1898 discovery of the mysterious, glowing element radium set off the commercial bonanza. Some product-makers found seemingly innocuous, legitimate uses for radium, uranium and other energy-emitting materials. Other entrepreneurs—and hucksters—however, exploited the widespread perception that radium had curative properties and used it to "enhance" whatever merchandise they were selling.

Fortunately, "for most products, the dose to the consumer was fairly small and the risk nonexistent," says Paul Frame, a health physicist at Oak Ridge Associated Universities and curator of the Health Physics Historical Instrumentation Collection. Most, that is, but not all. Check out this slide show to see radioactive gifts and gadgets that warmed the hearts of yesteryear—some that are truly eyebrow-raising, and some that are just anachronistically amusing.

Slide Show: "Hot" Products