Pica is usually described as a pathological craving for nonfoods, although it can mean a craving for substances generally accepted to be food as well. Medical science has long been interested in this disorder, for although it does not constitute a disease, it is often a symptom of disease and frequently is associated with nutritional deficiencies, especially those connected with minerals. In addition, psychiatry and psychology find that pica is often connected with mental problems, including those of retardation. Anthropologists study it as a cultural phenomenon, since it has been associated with some religions and also perhaps because the use of nonfoods is indicative of food shortages in the distant past.

The word “pica” comes from the Latin for “magpie,” a bird that eats practically anything. The term was first used by Ambroisé Pare in the 1500s, although references to pica consumption can be found in many ancient and medieval writings. M. H. Boezo, in his 1638 work De Pica, was the first to draw a distinction between “pica,” which he believed was an appetite for “absurd things,” and which was common in both men and women, and “malacia,” which referred to a voracious desire for normal food substances. He observed that the latter occurred most often in pregnant women, and believed the cause was a mental alteration caused by the pregnancy.