Because of its occurrence in the 238U decay chain, 226Ra exists naturally at low concentrations in uranium-containing minerals, soil, and groundwater.

In the early 20th century, when the hazards of radiation were not well-known, radium was commonly used in consumer items such as toothpaste and hair creams.

Radium was also formerly used as a radiation source for cancer treatment, but has since been replaced in this role by safer and more easily available alternatives.

Factory workers who worked with radium-containing luminous paint, known as the Radium Girls, often licked the tips of their paintbrushes in order to produce a finer point.

In doing so, the workers ingested some of the radioactive paint; this eventually led to serious health problems including cancer, bone damage, and anemia.