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Scientific Name(s): Hydrated aluminum silicate, Kaolin
Common Name(s): Argilla, Bolus alba, China clay, Heavy or light kaolin, Porcelain clay, White bole

Medically reviewed by Last updated on Feb 29, 2024.

Clinical Overview


Kaolin has traditionally been used internally to control diarrhea. Kaolin has also been used topically as an emollient and drying agent. Specifically, it has been used to dry oozing and weeping poison ivy, poison oak, and poison sumac lesions. It has also been used as a protectant for the temporary relief of anorectal itching and diaper rash.


Diarrhea: 12 years of age and older: 26.2 g after each loose stool every 6 hours until firm stool; do not exceed more than 262 g per 24 hours; do not use longer than 2 days. Younger than 12 years of age: seek advice from physician. Diaper rash: 4% to 20% kaolin-containing products applied topically. Radiation- and chemotherapy-induced mucositis: 15 mL of kaolin/pectin and diphenhydramine in a 50:50 mixture; hold in mouth for 3 minutes.


Contraindications have not yet been identified.


Kaolin-containing preparations are not absorbed. There are no data regarding kaolin in breast-feeding.


Kaolin pectin may decrease the absorption of drugs that chelate with aluminum salts (eg, digoxin, clindamycin, lincomycin). Until more information is available, avoid taking kaolin with drugs that chelate with aluminum. It may also decrease the absorption of trimethoprim and quinidine.

Adverse Reactions

Inhalation of kaolin through occupational exposure may cause pneumoconiosis.


Inhalation may predispose miners to pulmonary diseases.


Kaolin is a hydrated aluminum silicate. It occurs naturally as a clay that is prepared for pharmaceutical purposes by washing with water to remove sand and other impurities.(Windholz 1983)


Kaolin has been used commercially and medicinally for hundreds of years. It is currently used in the manufacture of pottery, bricks, cement, ceramics, paints, plastering material, color lakes (insoluble dyes), and insulators. As a raw material, it is commonly found in paper, plastics, cosmetics, and pharmaceuticals(Kwan 2006) and it is also used in pharmaceutical preparations as a filtering agent to clarify liquids. Evidence also suggests that kaolin may be useful in the decolorization of dye wastewater via the electrocoagulation method.(Zhuo 2007) When applied topically, it serves as an emollient and drying agent. When ingested, it acts as an adsorbent to bind GI toxins and control diarrhea.

Kaolin has been added to dusting powders and is used as a tablet excipient.


Kaolin has the approximate chemical formula of H2Al 2Si2O8 (H2O) and is a white or yellow-white powder that has a slightly oily feel. It is an environmentally benign aluminosilicate mineral(Sisterson 2003) that is insoluble in water.(Windholz 1983) Light kaolin is the preferred material for use in pharmaceutical preparations. The finely divided particles yield a very large surface area that adsorbs a wide variety of compounds.

Uses and Pharmacology


Venezuelan kaolin was tested in the presence of hydrochloric acid and pepsin in order to determine its neutralization capacity. Achievement of normal gastric pH occurred with 250 mg of the modified kaolin clay compared with 400 mg of original clay, leading to the conclusion that modified kaolin clay might be useful as a cheap and effective antacid.(Linares 2004)


The toxic effects of graphene oxide nanoparticles, often used in biomedical materials, was reduced by the addition of kaolin in rat dermal fibroblast cells in vitro.(Rozhina 2019)


Animal data

Older studies report a lack of evidence of benefit for the treatment of diarrhea in animals; however, kaolin has been given to small animals, foals, calves, lambs, and kids.(Kahn 2005, Rivera 1978)

Clinical data

Antidiarrheal preparations containing kaolin have been used in the treatment of enteritis, cholera, and dysentery. Kaolin preparations, however, have no intrinsic antibacterial activity and should not be used as the sole treatment in infectious diarrheas. When given orally, kaolin, especially light kaolin, adsorbs substances from the GI tract and increases the bulk of feces. Kaolin improves stool consistency within 24 to 48 hours; however, it does not decrease the number of stools passed or reduce the amount of fluids lost.(Berardi 2006, Wald 2003) Data regarding the effects of kaolin on travelers' diarrhea are lacking.(Ericsson 2005)

A network meta-analysis of data from randomized controlled trials (RCTs) and quasi-RCTs that studied interventions for acute diarrhea and gastroenteritis in children reported the efficacy of kaolin-pectin to be similar to that of controls (low certainty; very low quality).(Florez 2018)

Hemostatic agent

Animal data

Kaolin has been recognized as a coagulation activator and has been incorporated into various laboratory testing to measure activated clotting time (ACT)(Huyzen 1994), used to guide heparin anticoagulation to prevent thrombosis, and reduce inflammation.(Dalbert 2006)

Clinical data

The use of kaolin-soaked gauze or in other dressings in surgical procedures (including ear, nose, and throat, and cardiovascular surgery) as a hemostatic agent has been reported.(Chávez-Delgado 2014, Sairaku 2011, Trabattoni 2011) Compared to mechanical compression, use of kaolin-impregnated gauze pads was found to significantly improve access-site hemostasis (P<0.001) and mean compression time (P<0.001) in patients undergoing diagnostic coronary angiography in a small randomized, controlled trial (N=30).(Roberts 2017)

Kaolin-impregnated dressings are safe and effective hemostatic used after foot ulcer debridement in diabetic patients who were taking anticoagulants. Complete hemostasis at 5 minutes was achieved in 80% of kaolin dressing patients compared to only 40% in the control group (P=0.001) in a small randomized controlled trial (N=26).(Hwang 2019)


Kaolin has been used as an insecticide against various arthropods that affect crops.(Barker 2007, Barker 2006, Sackett 2005)

Laboratory testing

Kaolin has been used in the serodiagnosis of tuberculosis using the kaolin agglutination test (KAT).(Sarnaik 1993) Kaolin has also been used experimentally to induce hydrocephalus in animal models in order to assess the effects of the condition on sensorimotor development.(Khan 2006) Additionally, kaolin has been studied for its effects when testing horse serum for seroconversion against equine influenza virus, which causes a major respiratory disease among horses.(Boliar 2006)

Wastewater purification

One small study suggested that the addition of kaolin to oil field wastewater can result in removal of chemical oxygen demand, removal of scaling ions, such as iron, calcium, and magnesium, improvement in membrane filter index, bacteriocidal effects, and inhibition of corrosion.(Ma 2006)



12 years of age and older

26.2 g after each loose stool every 6 hours until firm stool; do not exceed more than 262 g per 24 hours; do not use longer than 2 days.(FDA 2004)

Younger than 12 years of age

Seek advice from physician.(FDA 2004)

Diaper rash

4% to 20% kaolin-containing products can be applied topically.(Rivera 1978)

Radiation- and Chemotherapy-Induced Mucositis

15 mL of kaolin/pectin and diphenhydramine in a 50:50 mixture; hold in mouth for 3 minutes.(Barker 1991)

Pregnancy / Lactation

Kaolin-containing preparations are not absorbed. There is a possible association between kaolin ingestion and the development of iron deficiency anemia and hypokalemia, especially during pregnancy.(Black 2003, Briggs 2005)

In a small study of female rats, hemoglobin, hematocrit, and red blood cell levels were reduced in the groups of rats that ingested a kaolin-containing diet. Additionally, the pups born to these rats exhibited low birth weights.(Patterson 1977)

There are no human data regarding breast-feeding and kaolin usage.(Briggs 2005)


Most drug interaction studies of kaolin have involved administration of kaolin pectin. Kaolin pectin can form insoluble complexes with a number of drugs and should be avoided in patients receiving drugs that may chelate with aluminum salts (eg, digoxin(Albert 1978, Albert 1981, Brown 1976) clindamycin(Albert 1978) lincomycin(Wagner 1966) and penicillamine(Ifan 1986). Until more information is available, interactions that occur with kaolin pectin should be considered to occur with kaolin alone. Additionally, concomitant administration of kaolin pectin and trimethoprim resulted in a reduced area under the curve for trimethoprim and decreased the average blood concentration of trimethoprim by 29.42%.(Babhair 1983) An in vitro study suggests that quinidine absorption may be reduced with concomitant administration of kaolin-pectin preparations.(Bucci 1981) To avoid potential drug interactions, kaolin should be used at least 3 hours before or after any other medications.(Pray 2006) When used topically for anorectal itching, petrolaturm or greasy ointments should be removed before applying kaolin-containing products in order to allow for proper adherence to the skin. Additionally, cocoa butter, cod liver oil, hard fat, lanolin, mineral oil, shark liver oil, petrolaturm, or white petrolaturm cannot be combined with kaolin because of limited skin adherence.(Berardi 2006)

Cardiac glycosides: Kaolin may decrease the serum concentration of cardiac glycosides. Monitor therapy. Only oral preparations of cardiac glycosides are expected to participate in this interaction.(Albert 1978, Albert 1981, Allen 1981, Brown 1976)

Chloroquine: Kaolin may decrease the serum concentration of chloroquine. Consider therapy modification.(Aralen October 2018, McElnay 1982, McElnay 1982)

Lincosamide antibiotics: Kaolin may decrease the absorption of lincosamide antibiotics. Monitor therapy. This interaction only applies to oral administration of lincosamide antibiotics.(Albert 1978, KAPECT 2010)

Quinidine: Kaolin may decrease the serum concentration of quinidine. Monitor therapy. Only oral preparations of quinidine and kaolin are expected to participate in this interaction.(Moustafa 1987)

Trimethoprim: Kaolin may decrease the serum concentration of trimethoprim. No action needed. This interaction only applies to oral administration of trimethoprim.(Gupta 1987)

Adverse Reactions

Inhalation of kaolin through occupational exposure may cause pneumoconiosis.(Altekruse 1984, Short 1993) Kaolin consumption has been associated with heavy metal intoxication, iron and other micronutrient deficiencies, and geohelminth infection.(Caillet 2019) A case of pica-related iron-deficiency anemia was reported in a 47-year-old male who began eating Kaolin white clay after watching a documentary entitled "Eat White Dirt." The anemia resolved after discontinuing clay consumption.(Attarha 2021)


Kaolin is highly insoluble and is not absorbed systemically. Therefore, it is not generally associated with severe toxicity. The toxicology of clays including kaolin used in food packaging has been reviewed, with no clear evidence of systemic toxicity reported.(Maisanaba 2015)

Inhalation of kaolin through occupational exposure may cause pneumoconiosis.(Altekruse 1984, Short 1993)



This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.

This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.

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