Food Facts

Facts About Geophagy: The Ancient Practice of Eating Clay

FFacts On Tap Editorial Team Fact-checked Updated February 21, 2026 4 min read

Long before dirt had a bad reputation, people around the world were eating it on purpose. Geophagy, the deliberate practice of consuming earth or clay, shows up in the historical record across Africa, the Americas, and Europe, tied to everything from pregnancy cravings to detoxification beliefs.

Here's what's actually known about this unusual but very real culinary and cultural tradition.

Geophagy is the practice of intentionally eating earth or clay-like substances, and it has been documented on nearly every continent throughout human history.
The ancient Greek physician Hippocrates wrote about the medicinal use of certain earths, and later Greek and Roman writers, including Pliny the Elder, described clay (such as 'terra sigillata') being used as a remedy for poisoning and stomach ailments.
Some Indigenous peoples of the Americas historically ate clay alongside foods like acorns and wild potatoes, since clay can bind bitter plant toxins (tannins and alkaloids) and make them safer to eat.
In parts of West and Central Africa, clay is traditionally sold in markets as a food item, often called 'calabash chalk' (also known as la craie or nzu), and is eaten for taste, cultural custom, and perceived health benefits.
Kaolin, a soft white clay, has been used both as a food additive and, historically, as an ingredient in some medicines like traditional anti-diarrheal remedies (kaolin was a component of the original Kaopectate formula).
Bentonite clay is rich in minerals such as calcium, magnesium, and iron, and its ability to absorb water and swell makes it useful in some skincare and industrial products, though eating it is not the same as safely absorbing those minerals nutritionally.
Craving and eating non-food substances such as clay, dirt, chalk, or ice is a recognized condition called pica, which appears more often during pregnancy and in people with iron-deficiency anemia.
Some researchers suspect pica for clay may be the body's attempt to cope with mineral deficiencies or gastrointestinal discomfort, but no controlled clinical studies have proven that eating clay reliably treats these conditions.
Not all clay is safe to eat: naturally occurring clay can contain heavy metals like lead and arsenic, parasites, or bacteria, so genuine food-grade edible clay is processed and tested before sale.
The U.S. Food and Drug Administration has issued warnings about certain imported edible clay products after finding elevated lead levels, underscoring that 'edible' labeling alone doesn't guarantee safety.
In Haiti, unleavened clay-based cookies known as 'bon bon terre' or clay cakes have historically been eaten, particularly by pregnant women, though public health officials have raised concerns about lead and parasite contamination in some batches.
Eating clay in large amounts can cause intestinal blockages, constipation, and interfere with the body's absorption of iron and zinc, which is the opposite of the 'mineral supplementation' benefit sometimes claimed.
Some potters and geologists distinguish edible clays like kaolin and bentonite from industrial or decorative clays, which are not intended for consumption and may contain additives or contaminants.
Modern 'detox' clay products marketed for internal use are sold as dietary supplements, meaning that in the U.S. they are not evaluated by the FDA for safety or effectiveness the way drugs are.

Frequently asked questions

What is geophagy?

Geophagy is the deliberate, culturally embedded practice of eating earth, soil, or clay, historically documented on nearly every continent for reasons ranging from perceived health benefits to religious or cultural custom.

Is eating clay safe?

It depends on the source and processing. Clay marketed and tested specifically as food-grade is generally considered lower-risk in small amounts, but raw or untested clay can contain heavy metals, parasites, or bacteria, and regulators have recalled contaminated products.

Why do pregnant women sometimes crave clay?

This falls under pica, a craving for non-food substances that appears more often during pregnancy and is associated with iron-deficiency anemia, though the exact cause isn't fully understood.

Does eating clay actually detoxify the body or supply minerals?

There isn't strong clinical evidence that eating clay meaningfully detoxifies the body or serves as a useful source of dietary minerals; in fact, clay can bind to and reduce the body's absorption of minerals like iron and zinc.

Where is edible clay traditionally eaten today?

Clay is still sold and consumed in parts of West and Central Africa (such as calabash chalk), in Haiti (as clay cookies), and among some Indigenous communities in the Americas, alongside modern commercial 'detox clay' supplements sold online.

Sources & further reading

Reviewed by the Facts On Tap Editorial Team

We write every article to be genuinely fun — and genuinely true. Each fact is checked against reputable sources before it goes live. Spotted something off? Tell us and read our fact-check policy.