A craving for unnatural foods such as clay, plaster, ashes, hair, starch, and dirt. The term derives from the word for magpie, a bird which is said to eat anything.Pica is a surprisingly prevalent tendency. It has been observed in retarded children, neurotic children, deprived groups, and pregnant women, as well as in chronic schizophrenic and senile patients who have apparently regressed to the stage where the child will put anything into its mouth, whether or not it is fit for consumption. Some normal children eat hair, mud, or the fluff from blankets for a short period.Pica is also a cultural practice found among peoples throughout the world. The most common form is geophagy, the eating of clay and dirt. In some localities these substances are consumed as part of the normal diet, but more often they are eaten for special purposes or only when food is scarce. In China the practice dates back to the fifth century. In Africa, warriors have long taken bags of dirt with them when they had to fight at distant points, in the belief that they would gain strength from consuming the earth of their homeland. In Malay and Polynesia, clay is eaten today to reduce weight, maintain a slender figure, and as a standard food during pregnancy. In Siberia and Tibet it is used as a remedy for vomiting and diarrhea, as well as to “fortify the heart.” In some areas “fossil meal,” a diatomaceous earth, is used as a relish or a delicacy in its own right. Clay- eating is also practiced as a primitive religious rite.In some cases pica is probably the result of a “specific hunger”—that is, an urge to eat substances which are needed but lacking in the body. This theory accounts for the fact that calcium-deficient children will sometimes eat chalk, plaster, or starch. The same type of explanation may also apply to some of the women who eat dirt during pregnancy, since the growing fetus requires extra minerals. However, according to Marcia Cooper (1957), who has made an extensive investigation of pica, this theory cannot account for the universality of the practice. She points out that the nutritive value of clay and dirt is almost nil, since these substances are inorganic and cannot be digested. Her own theory is that they were originally eaten during times of famine to fill the stomach and allay the pangs of hunger, and that later on some groups of people developed a taste for them, or a belief that they were effective for various disorders.Pica practices can be extremely injurious. Children who eat painted plaster or chew painted toys sometimes develop brain syndromes due to lead poisoning. Slaves brought to America from West Africa often continued to eat earth, primarily to kill hunger pangs. Each had his own “clay hole” in a secret location. As a result of the clay-eating many of them became lethargic, debilitated, and anemic, and some even died. The practice of earth-eating persists among some American Negroes; in fact, a study by Dunston (1961) showed an incidence of 42.9 per cent among the Negro population in one area. This form of pica is particularly prevalent among pregnant women in the rural South, who believe the earth will strengthen the child. It actually does the reverse, and is responsible for many infant deaths, since it leads not only to serious iron-deficiency anemia but to a lower hemoglobin rate. In New York City, where clay or earth is not available, women have been known to eat starch instead. A hospital recently reported that a woman patient under treatment for anemia had been consuming three full boxes of starch (about three pounds) every day.