Activated charcoal
Activated charcoal taken soon after a drug cut drug exposure in volunteer studies. In a trial of 4,632 people who self-poisoned, deaths did not differ with or without charcoal. In 5 volunteers, it did not reduce fecal gas. A dental review found insufficient evidence for charcoal toothpastes. It also blocks the absorption of medicines, and aspiration has damaged lungs.
- Status
- Sold over the counter in the US, in supplements, tablets and toothpastes. Used in emergency care for some poisonings.
- Also called
- activated carbon, medicinal charcoal, charcoal capsules, charcoal tablets, charcoal toothpaste, charcoal powder, AC
- Taken for
- detox, gas, bloating, smelly flatulence, hangover, cholesterol, teeth whitening, poisoning, overdose
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help2
Reported risks3
- ModerateShown to cut drug absorption in volunteer studies, by about 88% when taken within minutes of a drug and about 27% up to 4 hours later.
- LimitedCase reports: a patient who aspirated charcoal developed bronchiolitis obliterans and respiratory failure. A 2005 position paper calls charcoal contraindicated unless the airway is protected.
- LimitedLimited evidence: 3 low-quality studies of brushing with raw charcoal or soot reported more cavities and enamel wear.
What people take it for, and what was found
Shown to help2
Drug absorption after an overdose
Shown to cut drug absorption in healthy volunteers, by about 88% when given within 5 minutes and about 27% when given up to 4 hours later.
The numbers and sources
- Effect
- In 64 controlled volunteer studies, charcoal given 0 to 5 minutes after a drug cut median drug exposure by 88.4%, and by 27.4% when given up to 4 hours later [1]. In volunteer studies using at least 50 g, absorption fell by 47.3% at 30 minutes and 16.5% at 120 minutes [2].
- Population
- Healthy volunteers given test drugs [1][2].
- Sources
- [1], [2]
- Caveats
- Volunteer studies measure absorption, not clinical outcome. A 2005 position paper found no evidence that charcoal improves clinical outcome [2].
Cholesterol
One small report found 8 g three times a day lowered LDL by 41% in 7 adults with high cholesterol, with no control group described.
The numbers and sources
Not shown to help4
Survival after self-poisoning
Not shown to change survival after self-poisoning in 4,632 adults in Sri Lanka, with 6.3% dying on charcoal and 6.8% without.
The numbers and sources
- Effect
- In 4,632 people in Sri Lanka, mostly after pesticide or yellow oleander poisoning, 6.3% died with six 50 g doses against 6.8% with no charcoal (adjusted OR 0.96, 95% CI 0.70 to 1.33). No subgroup differed [3]. A 2021 systematic review of 296 human studies rated 83% of all studies low or very low quality, and found that some reported benefit when charcoal was given beyond one hour [4].
- Population
- Adults in three Sri Lankan hospitals [3]. Human, animal and in vitro poisoning studies [4].
- Sources
- [3], [4]
- Caveats
- The trial was open-label and funded by the Wellcome Trust [3]. Poisoning care happens in hospitals, not with supplements.
Intestinal gas and odor
One very small study found charcoal did not reduce sulfur gases, total gas or abdominal symptoms in 5 healthy adults.
Teeth whitening and oral health
Limited evidence: a review found no qualifying clinical trial of charcoal toothpastes or powders, and too little data to support their claims.
The numbers and sources
- Effect
- A literature review found no clinical trial of charcoal toothpastes or powders that met its criteria of randomization and 3 months of follow-up. It found insufficient clinical and laboratory data for their safety and efficacy claims [7].
- Population
- 118 articles screened [7].
- Sources
- [7]
- Caveats
- The review also checked 50 online products, and found antibacterial, antifungal and detoxification claims without supporting data [7].
Hangover and detox
Small trials found activated charcoal did not lower blood alcohol levels in volunteers. No trial measuring hangover symptoms or a wider detox effect was located.
The numbers and sources
- Effect
- In a randomized crossover study, 20 g of charcoal taken 30 minutes after 88 g of alcohol left plasma alcohol levels no different from water [9]. In 6 healthy adults, 60 g taken before drinking left the fraction of alcohol absorbed unchanged, and peak levels were 8% higher with charcoal (p = 0.08) [10]. In 9 men given 60 g at 1 and 3 hours after drinking, the area under the blood alcohol curve and the peak level did not differ from the same dose of alcohol alone, apart from a lower level at the 2 hour mark [11].
- Population
- Healthy adult volunteers, 6 to 11 per study [9][10][11].
- Sources
- [9], [10], [11]
- Caveats
- Three small studies from the 1980s, one non-randomized [11]. They measured blood alcohol, not hangover symptoms. The claim that charcoal clears toxins from the body in everyday use has no human study behind it that was located.
Doses studied
Poisoning studies used at least 50 g [2], or six 50 g doses at 4-hour intervals [3]. The gas study used 0.52 g four times a day [5], and the cholesterol report 8 g three times a day [6].
Risks
Reported risks3
Reduced absorption of medicines
Shown to cut drug absorption in volunteer studies, by about 88% when taken within minutes of a drug and about 27% up to 4 hours later.
The numbers and sources
- Effect
- Charcoal given within minutes of a drug cut median drug exposure by 88.4%, and still by 27.4% when given up to 4 hours later. Larger charcoal-to-drug ratios gave larger reductions [1].
- Population
- 64 controlled volunteer studies [1].
- Sources
- [1]
- Caveats
- Measured with drugs in overdose models. Effects on everyday medicines taken with supplement doses were not studied in this source.
Aspiration into the lungs
Case reports: a patient who aspirated charcoal developed bronchiolitis obliterans and respiratory failure. A 2005 position paper calls charcoal contraindicated unless the airway is protected.
The numbers and sources
- Effect
- A patient who aspirated activated charcoal developed bronchiolitis obliterans and respiratory failure, and a large amount of charcoal was found in the lungs after death [8]. The 2005 position paper states that charcoal is contraindicated unless the airway is intact or protected [2].
- Population
- Case report from overdose care [8].
- Sources
- [8], [2]
- Caveats
- Case reports cannot give a rate.
Enamel and teeth
Limited evidence: 3 low-quality studies of brushing with raw charcoal or soot reported more cavities and enamel wear.
The numbers and sources
- Effect
- In a dental review, 3 studies reported harmful outcomes from brushing with charcoal: more caries, enamel abrasion and an unquantified negative impact [7].
- Population
- Studies of raw charcoal or soot used for brushing [7].
- Sources
- [7]
- Caveats
- None of these studies met the review's quality criteria [7].
Claims tested and not found
Sources
- Jürgens G, Groth Hoegberg LC, Graudal N. The Effect of Activated Charcoal on Drug Exposure in Healthy Volunteers: A Meta-Analysis. Clinical Pharmacology & Therapeutics. 2009. https://doi.org/10.1038/clpt.2008.278
- American Academy of Clinical Toxicology, European Association of Poisons Centres and Clinical Toxicologists. Position Paper: Single-Dose Activated Charcoal. Clinical Toxicology. 2005. https://doi.org/10.1081/clt-200051867
- Eddleston M, Juszczak E, Buckley NA, et al. Multiple-dose activated charcoal in acute self-poisoning: a randomised controlled trial. The Lancet. 2008. https://doi.org/10.1016/s0140-6736(08)60270-6
- Hoegberg LCG, Shepherd G, Wood DM, et al. Systematic review on the use of activated charcoal for gastrointestinal decontamination following acute oral overdose. Clinical Toxicology. 2021. https://doi.org/10.1080/15563650.2021.1961144
- Suarez FL, Furne J, Springfield J, et al. Failure of Activated Charcoal to Reduce the Release of Gases Produced by the Colonic Flora. American Journal of Gastroenterology. 1999. https://doi.org/10.1111/j.1572-0241.1999.00798.x
- Kuusisto P, Manninen V, Vapaatalo H, et al. Effect of activated charcoal on hypercholesterolaemia. The Lancet. 1986. https://doi.org/10.1016/s0140-6736(86)90054-1
- Brooks JK, Bashirelahi N, Reynolds MA. Charcoal and charcoal-based dentifrices: A literature review. The Journal of the American Dental Association. 2017. https://doi.org/10.1016/j.adaj.2017.05.001
- Elliott CG, Colby TV, Kelly TM, et al. Charcoal Lung. Bronchiolitis obliterans after aspiration of activated charcoal. Chest. 1989. https://doi.org/10.1378/chest.96.3.672
- Hultén BA, Heath A, Mellstrand T, Hedner T. Does alcohol absorb to activated charcoal? Human Toxicology. 1986. https://doi.org/10.1177/096032718600500311
- Minocha A, Herold DA, Barth JT, et al. Activated charcoal in oral ethanol absorption: lack of effect in humans. Journal of Toxicology: Clinical Toxicology. 1986. https://doi.org/10.3109/15563658608990460
- Katona BG, Siegel EG, Roberts JR, et al. The effect of "superactive" charcoal and magnesium citrate solution on blood ethanol concentrations and area under the curve in humans. Journal of Toxicology: Clinical Toxicology. 1989. https://doi.org/10.3109/15563658909038576