Carbon processed to create an enormous internal surface area, which adsorbs many organic molecules onto its surface as it passes through the gut. It is a genuine emergency medicine for certain poisonings.
Activated charcoal works exactly as advertised — it adsorbs a very wide range of compounds — and that is precisely the problem with taking it as a supplement. In poisoning it is given as a single 50 g dose in hospital because binding a swallowed drug is the point. Taken at home for bloating or as part of a "cleanse", the same property binds nutrients and medication indiscriminately, including oral contraceptives, and there is no dependable evidence it does anything useful for wind. The marketing framing of removing toxins from the body is not how it works: it acts only on what is in the gut lumen at the time, not on anything already absorbed.
Grams of activated charcoal; surface area and particle size vary between products — a product without this marker may not resemble what was studied.
Also known as
Activated carbon, Medicinal charcoal
Regulation: A recognised medicine for acute poisoning and overdose, given in hospital. Sold separately as a dietary supplement with no pre-market efficacy review. EFSA authorised a claim that activated charcoal contributes to reducing excessive intestinal gas after eating, at 1 g at least 30 minutes before and 1 g shortly after a meal — one of the few authorised claims in this file, and a narrow one.
What the research used
The amounts, forms and durations published trials of Activated charcoal actually administered.
These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.
Studied for Excessive intestinal gas
1 g
Limited
Taken 30 minutes before and again shortly after a meal · Per meal
The regimen behind the authorised European claim. Trials of charcoal for bloating are small and inconsistent, and the claim rests on a narrow reading of that literature.
Studied for Acute poisoning (hospital use)
25–100 g
Moderate
Single dose of aqueous suspension, given by a clinician
Recorded to show the scale at which charcoal is used when the intention is genuinely to bind a substance in the gut. It is time-critical, clinician-directed and not a self-care intervention.
This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.
When it was taken
Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.
Each timing below was actually compared against an alternative in a trial, which is unusual.
⏳On an empty stomach
Moderate
It must be separated from medication, supplements and meals by at least two hours in either direction, because it adsorbs them. This is not a preference — it is the reason the product is a problem for anyone taking prescribed drugs.
Timing was tested. A trial compared this window against another and reported a difference.
The evidence in depth
Best supported: Limited
What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.
EFSA authorised a claim for reduction of excessive intestinal gas at 1 g before and after a meal. The underlying trials are small, old and inconsistent, and systematic assessments of charcoal for bloating describe the evidence as weak.
What may be going on: The porous carbon surface adsorbs gas-forming substrates and some gases within the gut lumen.
Limited evidence. Early human work, or mostly lab and animal research.
Activated charcoal is marketed for cleansing and liver support. It acts only within the gut lumen and does not remove anything already absorbed into the bloodstream or stored in tissue, and there is no human evidence supporting these claims.
Not enough evidence. Not enough human research to say anything useful yet.
No source is attached to this association yet, so it is rated not enough evidenceby default. It is listed because people commonly ask about it — not because there is evidence for it.
Things to know
Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.
Interaction
Adsorbs medication, including oral contraceptives
Interacts withOral contraceptives, levothyroxine, anticonvulsants, antidepressants, most oral drugs
Activated charcoal binds a very wide range of drugs and reduces their absorption. Reduced contraceptive efficacy is a documented and consequential example, and the same applies to thyroid hormone, antidepressants, anticonvulsants, antibiotics and most oral medication. Nothing should be taken within about two hours of it, and anyone on a drug where a missed dose matters should not take it at all.
Worth knowing
Aspiration risk
Charcoal aspirated into the lungs causes severe and sometimes fatal pneumonitis. This is why hospital administration is avoided in anyone with a reduced level of consciousness or an unprotected airway, and it is a reason not to give it to a drowsy or vomiting person at home.
Too much
Constipation and obstruction
Repeated dosing causes constipation and, in reported cases, bowel obstruction. It also binds nutrients, and prolonged use is a route to reduced absorption of vitamins and minerals from food.
Worth knowing
Black stools and dental staining
Stools turn black, which is harmless but can mask or mimic the black tarry stool of upper gastrointestinal bleeding. Charcoal toothpaste and powders are also abrasive to enamel.