Activated charcoal is a fine, odorless, black powder often used in emergency rooms to treat overdoses. Its toxin-absorbing properties have a wide range of medicinal and cosmetic uses, though none are scientifically proven.
Superheating natural sources of carbon, such as wood, produces activated charcoal. The black powder stops toxins from being absorbed in the stomach by binding to them. The body is unable to absorb charcoal, and so the toxins that bind to the charcoal leave the body in the feces.
Activated charcoal is not the same substance as that found in charcoal bricks or burnt pieces of food.
The manufacture of activated charcoal makes it extremely adsorbent, allowing it to bind to molecules, ions, or atoms. In this way, it removes these from dissolved substances.
Making activated charcoal involves heating carbon-rich materials, such as wood, peat, coconut shells, or sawdust, to very high temperatures.
This ‘activation’ process strips the charcoal of previously absorbed molecules and frees up bonding sites again. This process also reduces the size of the pores in the charcoal and makes more holes in each molecule, therefore, increasing its overall surface area.
As a result, one teaspoon full of activated charcoal has more surface area than a football field.
(Text taken from www.medicalnewstoday.com..... click for the full artical)
So it is not dangerous to eat - you'll hardly notice it in fact apart from the striking dark color!
I've used it here in the sour dough recipe
....standard recipe just with 5g of powder added to it.