Say the word “charcoal” to almost any American and the immediate mental image will be steaks on a grill. However, say that same word in an emergency department and the image will be drastically different.

A squeeze bottle of a black, thick solution; a nasogastric tube, and either a combative patient or an unconscious one will be the scenario. The use of activated charcoal in acute poisoning is an age-old practice dating back as far as as 1500 B.C.1


Medicinal activated charcoal is available in many different forms. It is a carbon molecular structure made from a variety of inert materials that have been treated with intense heat and oxygen, making it “activated.”1 This process yields a highly porous particle. It is estimated that a teaspoon of activated charcoal has a surface area of nearly 10,000 square feet.1

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The utility of activated charcoal in the treatment of acute poisoning and overdose is well-established. When administered orally, the porous particles selectively bind to (absorb) the toxic chemical. This carbon/toxin complex then passes out of the body intact. 

When given appropriately, activated charcoal absorbs up to 60% of the chemical toxins it encounters. The provider must understand, however, that this complex is unstable and can reverse over time. Consequently, a cathartic such as sorbitol is frequently coadministered to speed gastric emptying.2,3

Once the absorptive capacity of activated charcoal was established, investigators studied the possibility of using this substance to absorb other undesirable compounds in the body, such as cholesterol. One active control trial compared the efficacy of cholestyramine (Locholest, Prevalite, Questran) and activated charcoal in six patients with known hyperlipidemia.4 

After a one-week dietary control, the patients were given three weeks of each treatment on widely separate occasions. Activated charcoal reduced plasma cholesterol levels by an average of 5% more than did the cholestyramine. Since that time, however, more rigorous trials have failed to show any favorable difference between the two therapies. 

Another area of research for activated charcoal is the management of intestinal flatus. Since the deodorant action of charcoal was already accepted, researchers explored whether the ingestion of activated charcoal, either routinely or with a known gas-inducing meal, would reduce this common problem. Small-scale human trials failed to show appreciable reduction in sulfuric intestinal gases.5

Patients with irritable bowel syndrome also complain of bloating and large amounts of gas, but ingestion of activated charcoal has not proven useful in this population.6 Researchers experimenting with charcoal-impregnated undergarments in patients with excess flatus found that the only efficacious design was a brief with a middle layer of charcoal; this garment reduced odor by up to 75%.7

Activated charcoal is also widely used in water purification. For decades, the process of passing water through progressively fine-particle layers of charcoal was known not only to remove particulate matter but also to dissolve contaminants. This knowledge then became part of standardized water purification for medical uses such as hemodialysis.8 

The typical hemodialysis patient is exposed to more than 300 liters of water in one week. The water passes through the dialyzer cartridge, which is composed of multiple nonselective membrane fibers. Although this procedure has improved dramatically in the last two to three decades, the purity of the water is imperative, since contaminants can pass directly into the bloodstream.

 Consequently, the Association for the Advancement of Medical Instrumentation ( established standards for water purity that are also required by the Centers for Medicare & Medicaid Services.9 These approved standards rely heavily on activated charcoal for adequate water purification.

Safety, cost, how supplied

Activated charcoal is readily available at health-food stores and in general retail settings. The supplement is usually found as capsules filled with the fine powder. A usual capsule ranges from 500 mg to 600 mg and may be used one or two times daily.10 

A bottle of 100 capsules costs about $10. Many natural-based products such as toothpaste also contain activated charcoal for its odor-neutralization action and possible enamel-whitening action. 

Significant adverse reactions are rare, but users should be advised that their stools will be black. The main consideration is the concomitant consumption of a charcoal supplement and various medications; acetaminophen, oral contraceptives, tetracycline (Sumycin), and anticonvulsants are among the medications that can be rendered inactive by binding with charcoal. Routine use in young children is not recommended. 


The use of activated charcoal is not mainstream medicine. However, activated charcoal is a relatively benign product and certainly one that has withstood the test of time. With its relatively low risk profile, using this substance would be a neutral decision. 

No well-done clinical trials validate significant health benefits, but the results are not negative. Patients who feel that activated charcoal is helpful should be advised to avoid using it with other medications.

Sherril Sego, FNP-C, DNP, is a staff clinician at the VA Hospital in Kansas City, Mo., where she practices adult medicine and women’s health. She also teaches at the nursing schools of the University of Missouri and the University of Kansas.


  1. Activated charcoal. In: Jellin JM, ed. Nautral Medicines Comprehensive Database. Stockton, Calif.: Therapeutic Research Faculty (

  2. Bond GR. The role of activated charcoal and gastric emptying in gastrointestinal decontamination: a state-of-the-art review. Ann. Emerg Med. 2002;39(3):273-286.

  3. Isbister GK and Kumar VV. Indications for single-dose activated charcoal administration in acute overdose. Curr Opin Crit Care. 2011;17(4): 351-357.

  4. Park GD, Spector R, Kitt TM. Superactivated charcoal versus cholestyramine for cholesterol lowering: a randomized cross-over trial. J Clin Pharmacol. 1988;28(5):416-419.

  5. Suarez FL, Furne J, Springfield J, Levitt MD. Failure of activated charcoal to reduce the release of gases produced by the colonic flora. Am J Gastroenterol.1999;94(1):208-212.

  6. Whorwell PJ. The problem of gas in irritable bowel syndrome. Am J Gastroenterol. 2000;95(7):1618-1619.Available at

  7. Ohge H, Furne JK, Springfield J, et al. Effectiveness of devices purported to reduce flatus odor. Am J Gastroenterol. 2005;100(2):397-400.

  8. Azar AT, Ahmad S. Hemodialysis water treatment system. Studies in Computational Intelligence. 2013;404:347-378.

  9. Coulliette AD, Arduino MJ. Hemodialysis and water quality. Semin Dial. 2013;26(4):427-438.

  10. Mayo Clinic. Charcoal, activated (oral route). Available at

All electronic documents accessed April 15, 2014.