What Does Bentonite Do When Ingested? Exploring the Claims and Risks

October 30, 2025 •

5 min read

For centuries, some cultures have practiced geophagy, the consumption of earth, believing in its healing properties. The ancient practice of ingesting clay to supposedly absorb toxins and improve digestive health raises the question: what does bentonite do when ingested? While historically popular, modern medical professionals approach this practice with significant caution.

Quick Summary

Ingested bentonite clay, derived from volcanic ash, acts like a sponge in the digestive tract by binding to toxins and heavy metals due to its negative charge. It has been anecdotally used for detoxification and digestive relief, but faces major safety concerns, including heavy metal contamination and the risk of intestinal blockage.

Key Points

Binding Properties: When ingested, bentonite clay absorbs water and swells, allowing it to attract and bind to positively charged toxins and heavy metals in the digestive tract.
Potential Detoxification: It is traditionally and anecdotally used for internal detoxification, and some animal studies support its ability to bind to toxins like aflatoxins and heavy metals.
Digestive Effects: Historically and anecdotally, it's used to alleviate diarrhea, bloating, and constipation, with some limited human studies on IBS.
Risk of Heavy Metal Contamination: Bentonite clay can contain dangerous levels of heavy metals like lead, and the FDA has issued warnings and recalls for contaminated products.
Intestinal Blockage Danger: Without ample hydration, the clay can cause severe constipation or life-threatening intestinal blockages due to its expansion properties.
Interference with Medications: Its potent binding action can reduce the absorption and effectiveness of prescription medications and essential nutrients.
Unregulated Supplement: The FDA does not regulate all bentonite clay supplements, meaning product purity and safety cannot be guaranteed without independent testing.

How Ingested Bentonite Clay Works

Bentonite clay, also known as Montmorillonite, is an aged volcanic ash with unique physical and electrical properties that drive its purported health effects. When mixed with water, the clay particles absorb moisture and swell, transforming into a gel-like substance. This process is key to how it works in the body.

The Adsorption and Absorption Mechanism

Bentonite clay possesses a strong negative electrical charge. Most toxins and heavy metals in the body, such as lead, mercury, and cadmium, carry a positive charge. This difference in charge allows the clay to attract and bind to these unwanted substances in a process called adsorption. As the clay passes through the digestive tract, it is believed to act like a magnet and a sponge, carrying these bound toxins with it out of the body through the feces.

Mineral Exchange

In addition to its binding properties, bentonite clay contains numerous trace minerals, including silica, calcium, magnesium, and iron. As it binds to positively charged toxins, it simultaneously releases its own beneficial minerals for the body to utilize. This mineral exchange is sometimes cited as a nutritional benefit, though it's important to remember that most people get these minerals from their regular diet.

Potential Internal Benefits and Limited Evidence

Historically and anecdotally, ingested bentonite clay has been used for various internal ailments. However, it is crucial to understand that most of the scientific evidence for these benefits comes from animal studies or in-vitro tests, with a significant lack of robust human trials.

Digestive Support

Relief from Diarrhea: Some studies have shown that absorbent clays can help alleviate virus-related diarrhea by binding to pathogens. One older study found bentonite treatment effective for diarrhea from various causes.
Constipation and Bloating: The clay's ability to draw water into the intestines is thought to help relieve constipation and bloating, common symptoms of Irritable Bowel Syndrome (IBS).

Detoxification

Binding to Toxins: In animal studies, bentonite has shown effectiveness in binding to harmful toxins like aflatoxins, which can damage the liver. It has also demonstrated the ability to bind to heavy metals and pesticides.
Kidney and Liver Support: While animal studies have shown bentonite may aid the kidneys in filtering waste like urea and potentially detoxify the liver, human studies are lacking.

Gut Microbiome Health

By clearing out unwanted substances and providing minerals, bentonite clay is believed by some to create a healthier environment for beneficial gut bacteria to flourish. Research has shown that bentonite can have antibacterial properties against certain bacteria like E. coli.

Significant Risks and Critical Safety Concerns

Despite the purported benefits, ingesting bentonite clay carries several critical safety concerns that should not be overlooked. Medical professionals often advise caution and stress the need for consulting a doctor before consumption.

Heavy Metal Contamination

Perhaps the most serious risk is the potential for heavy metal contamination. Bentonite clay, as a natural mineral, can contain toxic levels of lead, arsenic, and mercury. The FDA has warned consumers and recalled certain products due to unsafe lead levels. Ingesting contaminated clay, especially over time, poses a risk of heavy metal poisoning.

Gastrointestinal Issues

If not consumed with a sufficient amount of water, the clay's absorbent and expansive properties can lead to severe constipation or even intestinal blockage. This is a serious condition that requires immediate medical attention.

Drug and Nutrient Interference

Bentonite's binding action is not selective; it can also bind to essential nutrients and medications, reducing their absorption and effectiveness. It is generally recommended to take bentonite clay at least two hours before or after other medications and nutritional supplements.

At-Risk Populations

Specific individuals should avoid ingesting bentonite clay, including pregnant or nursing women, older adults, and children, due to potential risks and the lack of safety data.

Comparison of Purported Benefits vs. Known Risks


Feature	Purported Internal Benefits (Anecdotal/Limited Study)	Known Internal Risks (Documented Concerns)
Mechanism	Binds to positively charged toxins like a magnet and sponge.	Binds indiscriminately to essential nutrients and medications.
Detoxification	Removes heavy metals and toxins from the gut.	Potential for heavy metal (lead, arsenic) poisoning from contaminated products.
Digestive Health	Can relieve diarrhea, constipation, and bloating.	Can cause severe constipation and intestinal blockage if not hydrated properly.
Mineral Content	Releases beneficial minerals like calcium and magnesium.	Can lead to mineral imbalances or electrolyte disturbances, such as hypokalemia (low potassium).
Scientific Basis	Primarily based on animal studies, in-vitro tests, and anecdotal reports.	Documented cases of contamination and physiological interference.
Overall Health	Supports gut health and immunity by removing pathogens.	Unregulated nature makes safety and purity unreliable.

Safe Practices When Considering Bentonite Clay

If you choose to ingest bentonite clay, following these precautions is essential, but it is always best to consult a healthcare professional first:

Use Food-Grade Clay: Only use bentonite clay that is specifically labeled as "food-grade" or "USP grade" from a reputable, third-party tested source.
Hydrate Adequately: Drink plenty of water throughout the day to prevent constipation or blockages.
Space from Medications: Do not take bentonite within two hours of taking medications or supplements to avoid interference.
Avoid Metal Utensils: Do not use metal spoons or containers when mixing bentonite clay, as this can deactivate its electrical properties. Use glass, ceramic, or wood instead.
Use for Short-Term Periods: Continuous, long-term use is not advised and can potentially cause mineral imbalances.
Discontinue if Adverse Effects Occur: Stop use immediately if you experience any signs of digestive discomfort, bloating, or other adverse reactions.

Conclusion

While bentonite clay has a long history of use as a traditional remedy for internal cleansing, the modern scientific understanding reveals a more complex picture. When ingested, its absorbent and adsorbent properties allow it to bind to substances in the digestive tract, which has been anecdotally and, in some animal studies, shown to help with detoxification and digestive issues. However, these potential benefits are shadowed by significant risks, most notably the danger of heavy metal contamination and the possibility of intestinal blockage. The lack of rigorous human studies and the unregulated nature of many supplements mean consumers must proceed with extreme caution. Consulting with a healthcare provider is paramount to understanding if there are any safe applications for your specific needs, particularly for at-risk individuals. Trusting regulated medical advice and proven treatments remains the safest path to wellness.

For more detailed information on supplement safety and regulatory oversight, visit the National Institutes of Health website at: https://www.nih.gov/.

Frequently Asked Questions

Ingesting bentonite clay carries significant risks, including potential heavy metal contamination, intestinal blockage, and interference with medications. It is not generally recommended without consulting a healthcare professional.

It is claimed that bentonite clay binds to negatively charged toxins and heavy metals in the digestive tract, carrying them out of the body. However, this is largely anecdotal or based on limited animal studies, with no strong evidence of its effectiveness in humans.

Food-grade bentonite clay is intended for human consumption and is supposed to be tested for purity, although regulatory oversight can be lacking. Non-food-grade is for external or industrial use and should never be ingested due to higher contamination risks.

While bentonite clay draws water into the intestines, potentially relieving constipation, its highly absorbent nature means it can also cause severe constipation or intestinal blockage if not consumed with sufficient water. Consult a doctor before use.

In animal studies, bentonite clay has shown an ability to bind to heavy metals, but there is insufficient evidence to prove its effectiveness or safety for human heavy metal detoxification. There is also a risk of ingesting lead from contaminated products.

Choose a product specifically labeled "food-grade" or "USP grade" from a reputable brand. Look for third-party lab testing and consult with a healthcare professional to discuss your options.

Pregnant or nursing women, children, older adults, and individuals with certain medical conditions should avoid ingesting bentonite clay. Anyone on medication should also be cautious, as it can interfere with absorption.