Bentonite Clay and Swallowing Claims: Lead and Interaction Concerns

Do not treat bentonite clay as a safe thing to swallow. The sources we read say the safety of eating clay is not fully established, that clay composition varies, and that some healing clays contain toxic metals. [1] [2] If a large amount was swallowed, or a child or pregnant person ate clay, call Poison Help at 1-800-222-1222 or ask a clinician. This page gives no amounts and no how-to steps.

What bentonite is

Bentonite is a natural clay made mostly of montmorillonite, with other minerals such as feldspar, calcite and quartz. [3] A 2024 review describes bentonites and montmorillonites as natural clay minerals originating from volcanic ash. [4] Dermatology is one area of research interest. For skin use and the basics, see Bentonite Clay: Skin Use, Swallowing Claims and Lead and the different clay in Kaolin Clay.

The claims, checked

Lead, arsenic and other metals

• A 2020 laboratory study found high concentrations of arsenic and lead in experimental samples of a therapeutic clay. The paste tested was a green clay applied to mice for 2 weeks, and lead was elevated in the liver and kidneys of treated mice; the authors reported no measurable biological effect and advised caution. [2] That product was not necessarily bentonite, and animal findings do not show what happens in people.
• A 2018 review says clay can adsorb toxic elements and also make them available through ingestion or through skin. [6]
• A 2015 review reports that oral exposure to clays is common, intentional and unintentional, and that toxic effects could come from changed exposure to mineral elements. [7]
• The clay mix varies. A 2022 geophagy review says the chemical composition of clay may vary from one region to another. [1]

We did not find a source we could read that reports lead or arsenic levels across bentonite products sold today, so we cannot say how common contamination is. See Heavy Metals in Natural Ingredients and Product Quality and Contamination.

Eating clay in pregnancy and childhood

• A review of clay eating during pregnancy (French Guiana experience) says clay consumption may lead to iron deficiency and possible overexposure to heavy metals, including aluminium. [8]
• A 2003 review of 15 women with severe lead poisoning in pregnancy found that the Hispanic women among them (70%) all developed it from eating soil, clay or pottery, and notes that lead freely crosses the placenta. [9] Those were soil, clay or pottery rather than a named bentonite product.
• Children, breastfeeding, older adults, liver and kidney disease, allergy and pre-surgery: not described in the sources we read for bentonite, so we make no claims.

Medicines

Proper evidence not found for documented bentonite and medicine interactions in human sources. We searched PubMed for clay, bentonite, kaolin and attapulgite with oral drug absorption and found environmental and materials papers only. Absence of evidence is not proof of safety. Ask a pharmacist before swallowing any clay product if you take regular medicines. See Natural Ingredient and Medicine Interactions and How Interactions Work. For a contrasting substance that does bind medicines, see Activated Charcoal.

What a reader can safely do

• Check with a clinician or pharmacist before swallowing any clay.
• Read labels for the exact clay and any testing for metals, and see Natural Substances Not Meant to Be Swallowed.
• Do not put clay on serious, infected or worrying skin; see a clinician instead.
• For detox claims in general, read Detox Claims.