Pica, or the practice of eating dirt or clay, is comparatively common. Many people feel that a clay bar (about twice the size of a candy bar) once a week can relieve irritability, constipation, mineral deficiencies and heart burn. There is some evidence that this might, in fact, be true.

Pregnant women (all over the world) have been known to have intense cravings for dirt. However, most dirt is contaminated with paint chips, which are made of lead. When the blood of a group of such women was tested it was found that they had mild mineral deficiencies (compared to the women with no cravings). Still none of these studies are conclusive, and there are many complications that can arise from eating too much dirt or contaminated dirt. So you probably don’t need to go out and get yourself a handful just yet.

A pica is a unit of measurement equalling 1/6 of an inch or 4.24 millimeters. A remnant of old-school typesetting, newspapers and magazine production rooms in the United States and United Kingdom still use picas as their unit of measurement. This can be seen in layout programs such as QuarkXPress and PageMaker, which allows designers to display rulers in inches, picas, ciceros and points. Many physical production rulers, called pica sticks in American newsrooms, also have these four units of measurements on them.

In layout design, a good rule of thumb is that every element should be set at least one pica away from every other element on the page. In other words, one pica should separate columns of text, one pica should set headlines away from body text, text should be one pica away from border lines, and so on.

Under the Anglo-Saxon system of typesetting, a point is defined as 1/72 of an inch, or .353 millimeters. A pica equals 12 points, which would also be the height of a twelve point font in typography using this system.


Pica is Latin for "magpie", which is a bird known for its unusual tastes. It tends to carry off and eat extremely bizarre objects, considering everything from tinfoil to rubber bands to be tasty treats.

Pica specifically refers to a compulsive craving for nonnutritive substances that persists for more than a month. Medical texts name picas by adding the Greek suffix phagia to whatever substance the patient is attracted to. For example, ice cube crunchers are said to suffer from pagophagia, people who munch cigarette ashes have stachtophagia, and dirt and dust eating are known, respectively, as geophagia and corniophagia.

Picas are by no means limited to organic substances; an incomplete list of picas includes air freshener (especially the solid gel type), concrete (think of the dental bills!), cardboard, paint chips (particularly dangerous, as house paint can contain lead), toothpaste, rubber (remember the kid who ate erasers in class?), silicone, plastic, and wood (I am a reformed pencil chewer, but I don't recall actually ingesting the splintery remains of my handiwork).

Other common picas include broken crockery, hair, cotton, burnt match heads, starch (such as cornstarch and laundry starch), coffee grounds, baking soda, rust, and glue or paste (perhaps Ralph Wiggum has pica?). Those suffering from pica are often ashamed of their cravings and will go to great lengths to hide any evidence of their strange gustatory inclinations. This can make the condition difficult to diagnose and treat, sometimes to the profound detriment of the patient.

Prior to 1995 or so, pica was considered to be an exclusively psychiatric disorder, and is still listed as such in the DSM. It was and is lumped in with such eating disorders as anorexia nervosa and bulimia, but the view on some picas is changing. Geophagia, for example, is particularly common worldwide; the Pomo Indians of California and Italians in Sardinia traditionally mixed clay with pounded acorns to make bread (the clay neutralized the tannic acid present in the acorns and makes the bread palatable). Archaeological evidence proves that Homo Erectus was a clay eater, and many Africans have a craving for clay from termite mounds. Chemical analysis of termite mound soil revealed a composition high in kaolinic clays, the very same base used in Kaopectate, which is ingested in more "civilized" societies for upset stomachs. Chemists and physical geographers decided to examine soil samples from North Carolina, China, and Zimbabwe that were locally considered medicinal. The deposits from China and North Carolina were chock full of minerals (including iron, potassium, and calcium) largely deficient in the local diets. The most common pica, ice chewing (pagophagia), is generally indicative of iron deficiency. One case study involves a man admitted to the hospital for uncontrolled bleeding from his nose and hemorrhoids. He was chewing up to five trays of ice a day. Turns out he was suffering from severe iron deficiency and required supplements and transfusions to save his life. Anyone who compulsively chews ice or anything else should be checked for iron deficiency, though no one knows why a lack of iron drives people to crunch frozen water rather than, say, eat iron filings.

In the American Deep South, where eccentricities of all stripes tend to be tolerated and even celebrated, it's not uncommon to find hunks of clay on sale in grocery store produce departments. I was raised in Charleston, South Carolina and vividly recall shopping trips with my mother. I remember the styrofoam trays - the same ones used for grapes and meat - piled high with little slabs of creamy dirt, cellophane-wrapped and ready for purchase. I haven't seen clay on sale at the local Piggly Wiggly in quite a few years; Charleston has undergone an image upgrade for the tourist industry, and I'm sure that dirt-eating wouldn't play too well with the majority of visitors to our fair city. (My husband thinks the FDA may frown on dirt-peddling as well.) You don't have to go too far off the beaten path anywhere in the South, though, to find the loamy delicacy being sold in small country stores. From what I understand, many women begin to eat dirt while pregnant, and a theory exists that certain clays contain mineral deposits beneficial to a developing fetus. Geophagia tends to be tough to kick, and people who find a particularly tasty dried-up riverbed or clay deposit sometimes guard their secret stash fiercely. There is a small but mostly friendly community of geophagics online which, unlike most so-called "psychiatric disorder support groups", engage in spirited discussions of what type of dirt is tastiest and participate in the ongoing quest to find new and better clay deposits.

Source: Eat Drink & Be Merry, Dean Edell, M.D. copyright 1999

Pi"ca (?), n. [L. pica a pie, magpie; in sense 3 prob. named from some resemblance to the colors of the magpie. Cf. Pie magpie.]

1. Zool.

The genus that includes the magpies.

2. Med.

A vitiated appetite that craves what is unfit for food, as chalk, ashes, coal, etc.; chthonophagia.

3. R. C. Ch.

A service-book. See Pie.


4. Print.

A size of type next larger than small pica, and smaller than English.

⇒ This line is printed in pica

Pica is twice the size of nonpareil, and is used as a standard of measurement in casting leads, cutting rules, etc., and also as a standard by which to designate several larger kinds of type, as double pica, two-line pica, four-line pica, and the like.

Small pica Print., a size of type next larger than long primer, and smaller than pica.

⇒ This line is printed in small pica


© Webster 1913.

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