charcoal is perfectly safe to have not just in your mouth but in your gut... its got electrostatic charges on it that attract a lot of toxic chemicals and metabolies and the actual pathological organisms, in fact, if you go look up some old funny history about Russian cars, they often came with kits out of the factory in the glovebox including charcoal pills

i personally love the taste of meat that has been roasted over fire and coals and has a crisp edge of charcoal, even though probably some parts of that are carcinogenic, the rest of the meat makes up for it

i use a shampoo at the moment that has charcoal in it too, and out of all of the many different varieties, and including plain old sodium based bar soap, it leaves my hair the happiest (so i also am thinking i should add charcoal when i make some liquid tallow soap really soon)

charcoal and carbon are extremely interesting and important materials for human health

you just might want to make sure of where it comes from and what else they add to it... plain old lab grade finely divided, sulphuric acid activated carbon is perfectly safe, the residual sulphate won't hurt you at all, and i know from using it in chemistry that all the nasty things tend to stick to it and then it flushes through and thus it helps clean you out

reminds me

shit... i should be taking charcoal