Activated charcoal absorbs a wide variety of drugs and chemicals. Adsorption is a process in which atoms and molecules move from a bulk phase (such as a solid, liquid, or gas) onto a solid or liquid surface. In other words, the toxic substance attaches to the surface of the charcoal. Because charcoal is not “digested,” it stays inside the GI tract and eliminates the toxin when the person has a bowel movement.
This mechanism of action should not be confused with absorption. Absorption occurs when a substance passes into or through a tissue, like water passing into a sponge. Once the chemical or drug has been absorbed by the GI tract, activated charcoal can no longer retrieve the toxic ingestion. It will only attach to substances that are still inside the stomach or intestines.
The charcoal is “activated” because it is produced to have a very fine particle size. This increases the overall surface area and adsorptive capacity of the charcoal. It is produced by adding acid and steam to carbonaceous materials such as wood, coal, rye starch, or coconut shells. To put this in perspective, one standard 50-gram dose of activated charcoal has the surface area of 10 football fields.
Activated charcoal is often combined with sorbitol (a substance that stimulates the bowels to move, like a laxative) to shorten the amount of time to move through the system and reduce the possibility of constipation. However, to avoid adverse effects, sorbitol is not given with every dose of activated charcoal.
All efforts should be made to reduce adsorption of severely toxic substances, as activated charcoal does not bind as well with these substances:
Lithium (Eskalith, Lithobid), strong acids and bases, metals and inorganic minerals such as sodium, iron, lead, arsenic, iodine, fluorine, and boric acid.
Alcohol (such as ethanol, methanol, isopropyl alcohol, glycols, and acetone)
Hydrocarbons (such as petroleum distillates and plant hydrocarbons such as pine oil)
Activated charcoal does not irritate the mucous membranes of the GI system. In addition to adsorption of toxins, activated charcoal also adsorbs food nutrients, vitamins, and minerals. However, this short-term effect is not a concern when activated charcoal is used to treat