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Clay is a type of fine-grained soil that in some areas, particularly developing countries and poor communities, people eat for potential medicinal purposes. This practice is called "pica" or "geophagia," and an individual's specific appetite for these substances may result from mineral deficiencies, such as iron deficiency, cultural tradition, or pregnancy. Clay is used orally for diarrhea, gastrointestinal disorders, irritable bowel syndrome (IBS), mercury poisoning, and nausea.

Also known as:  Arcilla, Argile, Dioctahedral Smectite. Beidellitic Montmorillonite, Calcium Montmorillonite, Dioctahedral Smectite, Montmorillonite de Calcium, Montmorillonite Beidellitique, Smectite Dioctaédrique

Diseases and Conditions

There is insufficient reliable information available about the effectiveness of clay.


Clay may be safe to use orally in the short-term, but unsafe for long-term use. Calcium montmorillonite clay in doses of 1.5 to 3.0 grams daily has been shown to be safe for up to 3 months. It may be unsafe for pregnant women to consume clay orally; ingestion has been associated with increased risk for preeclampsia, hypertension, and edema among women in term. There is insufficient information on the safety of clay for children and breastfeeding women; best to avoid. The risk for adverse effects associated with clay increase with habitual ingestion; these include painful heart palpitations, heart lesions, skin ulcerations, dry and shiny skin, diarrhea, constipation, loss of appetite, flatulence, vomiting, intestinal obstruction, enlarged liver and spleen, excessive urination, iron deficiency and iron malabsorption, anemia, muscle weakness and swelling, lead poisoning and damage to the central nervous system in children, and pulmonary disorders.

Medication Interactions

Clay has moderate interactions with cimetidine and quinine. Clinical research has suggested that clay may inhibit the absorption of cimetidine when taken simultaneously and that consumption of clay along with cimetidine might reduce the effectiveness of cimetidine therapy. In vitro evidence has suggested that consuming clay reduces the bioavailability of quinine by about thirty percent, which means that consumption of clay along with quinine might reduce the effectiveness of quinine therapy.

Supplement and Food Interactions

Clay may have interactions with iron, potassium, and zinc. Clay can interfere with iron absorption, therefore, consuming clay along with iron supplements might decrease the effects of iron. Clay also possesses potassium-binding capacity, and chronic clay ingestion has been associated with severe hypokalemia. In theory, consuming clay along with potassium supplements might decrease the effects of potassium. Lastly, clay can interfere with zinc absorption, therefore, consuming clay along with zinc supplements might decrease the effects of zinc.


For the treatment of irritable bowel syndrome, it is recommended to take three grams of beidellitic montmorillonite three times daily for eight weeks.


Clay is not regularly found in foods.

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