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Medically reviewed by Last updated on April 22, 2021.

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

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.


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 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.(1)


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 pharmaceuticals2 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.3 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 mineral4 that is insoluble in water.1 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


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.5, 6

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.7, 8 Data regarding the effects of kaolin on travelers' diarrhea are lacking.9

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)10, used to guide heparin anticoagulation to prevent thrombosis, and reduce inflammation.11

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.12, 13, 14

Other uses


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.15


Kaolin has been used as an insecticide against various arthropods that affect crops.16, 17, 18

Laboratory Testing

Kaolin has been used in the serodiagnosis of tuberculosis using the kaolin agglutination test (KAT).19 Kaolin has also been used experimentally to induce hydrocephalus in animal models in order to assess the effects of the condition on sensorimotor development.20 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.21

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.22



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.23

Younger than 12 years of age

Seek advice from physician.23

Diaper rash

4% to 20% kaolin-containing products can be applied topically.5

Radiation- and Chemotherapy-Induced Mucositis

15 mL of kaolin/pectin and diphenhydramine in a 50:50 mixture; hold in mouth for 3 minutes.24

Pregnancy / Lactation

Because kaolin-containing preparations are not systemically absorbed and do not cross the placenta, kaolin is listed as Pregnancy Category C. However, there is a possible association between kaolin ingestion and the development of iron deficiency anemia and hypokalemia, especially during pregnancy.25, 26

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.27

There are no human data regarding breast-feeding and kaolin usage.25


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, digoxin28, 29, 30 clindamycin31 lincomycin32 and penicillamine33. 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%.34 An in vitro study suggests that quinidine absorption may be reduced with concomitant administration of kaolin-pectin preparations.35 To avoid potential drug interactions, kaolin should be used at least 3 hours before or after any other medications.36 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.7

Adverse Reactions

Inhalation of kaolin through occupational exposure may cause pneumoconiosis.37, 38


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.39

Inhalation of kaolin through occupational exposure may cause pneumoconiosis.37, 38


1. Windholz M, ed. The Merck Index. 10th ed. Rahway, NJ: Merck & Co; 1983.
2. Kwan CC, Chu WH, Shimabayashi S. Effect of polyvinylpyrrolidone and sodium lauroyl isethionate on kaolinite suspension in an aqueous phase. Chem Pharm Bull. 2006;54(8):1082-1087.16880648
3. Zhuo Q, Ma H, Wang B, Gu L. Catalytic decolorization of azo-stuff with electro-coagulation method assisted by cobalt phosphomolybdate modified kaolin. J Hazard Mater. 2007;142(1-2):81-87.17005320
4. Sisterson MS, Liu YB, Kerns DL, Tabashnik BE. Effects of kaolin particle film on oviposition, larval mining, and infestation of cotton by pink bollworm (Lepidoptera: Gelechiidae). J Econ Entomol. 2003;96(3):805-810.12852620
5. Rivera ER, Armstrong WD, Clawson AJ, Linnerud AC. Effect of dietary oats and kaolin on performance and incidence of diarrhea of weanling pigs. Journal of Animal Science. 1978;46(6):1685-1693.
6. Kahn CM, ed. The Merck Veterinary Manual. 9th ed. Whitehouse Station, NJ: Merck & Co; 2005:1984-1985.
7. Berardi RR, Kroon LA, McDermott JH, et al. Handbook of Nonprescription Drugs. 15th ed. Washington, DC: American Pharmacists Association; 2006:340,357,358,769.
8. Wald A. Constipation, diarrhea, and symptomatic hemorrhoids during pregnancy. Gastroenterol Clin North Am. 2003;32(1):309-322.12635420
9. Ericsson CD. Nonantimicrobial agents in the prevention and treatment of travelers diarrhea. CID. 2005;41(suppl 8):S557-S563.16267719
10. Huyzen RJ, Harder MP, Huet RC, Boonstra PW, Brenken U, van Oeveren W. Alternative perioperative anticoagulation monitored during cardiopulmonary bypass in aprotinin-treated patients. J Cardiothorac Vasc Anesth. 1994;8(2):153-156.7515704
11. Dalbert S, Ganter MT, Furrer L, Klaghofer R, Zollinger A, Hofer CK. Effects of heparin, haemodilution and aprotinin on kaolin-based activated clotting time: in vitro comparison of two different point of care devices. Acta Anaesthsiol Scand. 2006;50(4):461-468.16548858
12. Chávez-Delgado ME, Kishi-Sutto CV, Albores de la-Riva XN, et al. Topic usage of kaolin-impregnated gauze as a hemostatic in tonsillectomy. J Surg Res. 2014 Dec;192(2):678-85.24952410
13. Sairaku A, Nakano Y, Oda N, et al. Rapid hemostasis at the femoral venous access site using a novel hemostatic pad containing kaolin after atrial fibrillation ablation. J Interv Card Electrophysiol. 2011;31(2):157-164.21336615
14. Trabattoni D, Montorsi P, Fabbiocchi F, et al. A new kaolin-based haemostatic bandage compared with manual compression for bleeding control after percutaneous coronary procedures. Eur Radiol. 2011;21(8):1687-1691.21476127
15. Linares CF, Rosa-Brussin M. Modified Venezuelan kaolin as possible antacid drug. J Applied Sci. 2004;4(3):472-476.
16. Barker JE, Holaschke M, Fulton A, Evans KA, Powell G. Effects of kaolin particle film on Myzus persicae (Hemiptera: Aphididae) behaviour and performance. Bull Entomol Res. 2007;97(5):455-460.17916264
17. Barker JE, Fulton A, Evans KA, Powell G. The effects of kaolin particle film on Plutella xylostella behaviour and development. Pest Manag Sci. 2006;62(6):498-504.16602083
18. Sackett TE, Buddle CM, Vincent C. Effect of kaolin on fitness and behavior of Choristoneura rosaceana (Lepidoptera: Tortricidae) larvae. J Econ Entomol. 2005;98(5):1648-1653.16334335
19. Sarnaik RM, Sharma M, Kate SK, Jindal SK. Serodiagnosis of tuberculosis: assessment of kaolin agglutination test. Tuber Lung Dis. 1993;74(6):405-406.8136495
20. Khan OH, Enno TL, Del Bigio MR. Brain damage in neonatal rats following kaolin induction of hydrochephalus. Exp Neurol. 2006;200(2):311-320.16624304
21. Boliar S, Stainislawk W, Chambers TM. Inability of kaolin treatment to remove nonspecific inhibitors from equine serum for the hemagluttination inhibition test against equine H7N7 influenza virus. J Vet Diagn Invest. 2006;18(3):264-267.16789714
22. Ma HZ, Wang B. Multifunctional microsized modified kaolin and its application in wastewater treatment. J Hazard Mater. 2006;136(2):365-370.16431021
23. Part 335—Antidiarrheal drug products for over-the-counter human use. Food and Drug Administration HHS. Accessed December 19, 2007.
24. Barker G, Loftus L, Cuddy P, Barker B. The effects of sucralfate suspension and diphenhydramine syrup plus kaolin-pectin on radiotherapy-induced mucositis. Oral Surg Oral Med Oral Pathol. 1991;71(3):288-293.1707149
25. Briggs GG, Freeman RK, Yaffe SJ, eds. Drugs in Pregnancy and Lactation. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005:875.
26. Black RA, Hill DA. Over-the-counter medications in pregnancy. Am Fam Physician. 2003;67(12):2517-2524.12825840
27. Patterson EC, Staszak DJ. Effects of geophagia (kaolin ingestion) on the maternal blood and embryonic development in the pregnant rat. J Nutr. 1977;107(11):2020-2025.561832
28. Albert KS, Ayres JW, DiSanto AR, et al. Influence of kaolin--pectin suspension on digoxin bioavailability. J Pharm Sci. 1978;67(11):1582-1586.712596
29. Brown DD, Juhl RP. Decreased bioavailability of digoxin due to antacids and kaolin-pectin. N Engl J Med. 1976;295(19):1034-1037.972657
30. Albert KS, Elliot WJ, Abbott RD, Gilbertson TJ, Data JL. Influence of kaolin-pectin suspension on steady-state plasma digoxin levels. J Clin Pharmacol. 1981;21(10):449-455.7309906
31. Albert KS, DeSante KA, Welch RD, DiSanto AR. Pharmacokinetic evaluation of a drug interaction between kaolin--pectin and clindamycin. J Pharm Sci. 1978;67(11):1579-1582.712595
32. Wagner JG, et al. Design and data analysis of biopharmaceutical studies in man. Can J Pharm Sci. 1966;1:55-68.
33. Ifan A, Welling PG. Pharmacokinetics of oral 500-mg penicillamine: effect of antacids on absorption. Biopharm Drug Dispos. 1986;7(4):401-405.3021251
34. Babhair SA, Tariq M. Effect of magnesium trisilicate and kaolin-pectin on the bioavailability of trimethoprim. Res Commun Chem Pathol Pharmacol. 1983;40 (1):165-168.6306744
35. Bucci AJ, Myre SA, Tan HS, Shenouda LS. In vitro interaction of quinidine with kaolin and pectin. J Pharm Sci. 1981;70(9):999-1002.6101170
36. Pray WS, ed. Nonprescription Product Therapeutics. 2nd ed. Baltimore, MD: Lippincott Williams & Wilkins; 2006:176,199,620,631,841.
37. Short SR, Petsonk EL. Respiratory health risks among nonmetal miners. Occup Med. 1993;8(1):57-70.8456349
38. Altekruse EB, Chaudhary BA, Pearson MG, Morgan WK. Kaolin dust concentrations and pneumoconiosis at a kaolin mine. Thorax. 1984;39(6):436-441.6463912
39. Maisanaba S, Pichardo S, Puerto M, et al. Toxicological evaluation of clay minerals and derived nanocomposites: a review. Environ Res. 2015 Apr;138:233-54.25732897


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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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