I thought that was charcoal
, which is very different from actual coal.
Only thing they have in common is the large amounts of carbon, and the colour.
If by actual coal you mean the fossil stuff, then yes, it's quite different and I don't know of any case where it is administered orally (except perhaps in homoeopathy*). In German we don't usually differentiate between charcoal and coal (at least I don't). We have Steinkohle and Holzkohle, which can be translated as woodcoal and stonecoal, but usually we just say coal or rather Kohle.
*Probably not. Found one source only that was about testing it as a potential homoeopathic medicine.
Edit: Oh, found some more. Seems like it has veterinary uses - or is believed to have.