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Kaolin (hydrated aluminum silicate)

Common Name(s)

Heavy or light kaolin, China clay, bolus alba, porcelain clay, white bole, argilla

What is Kaolin (hydrated aluminum silicate)?

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.

What is it used for?

Traditional/Ethnobotanical uses

Kaolin has been used commercially and medicinally for hundreds of years. It is currently found in the manufacture of pottery, bricks, cement, plastering material, color lakes (insoluble dyes), and insulators. As a raw material, it is commonly found in paper, plastics, cosmetics, and pharmaceuticals, and it is also used in pharmaceutical preparations as a filtering agent to clarify liquids.

General uses

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 rashes. It has also been used as a protectant for the temporary relief of anorectal itching and diaper rash.

What is the recommended dosage?

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.


FDA Pregnancy: Category C. Kaolin does not cross the placenta. There are no data regarding kaolin in breast-feeding.


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

Side Effects

Inhalation of kaolin through occupational exposure may cause pneumoconiosis.


Inhalation may predispose miners to pulmonary diseases.


1. Kaolin. Review of Natural Products. Facts & Comparisons 4.0. June 2008. Accessed July 22, 2008.

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Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.