Charcoal is a good to use in the field when you suspect you have eaten some types of poisonous plants (youll know by your gutts heaving and all the puking going on), it will not work for heavy metals or acids. To my knowledge constipation is the primary concern when using charcoal. The difference between activated charcoal and the charcoal from your fire is the activated charcoal is ground to a fine powder. The difference will cause a change in dosage smaller with activated. Don’t use charcoal briquettes some of them have chemicals in them that may do more harm than good