Is activated charcoal effective against food poisoning, and gas etc? are there any side effects from taking it?

SaveItForABarbeque: Activated charcoal adsorbs lots of stuff but is not used for"food poisoning"unless due to a toxic chemical,not the type of food poisoning from bacteria or viruses. Some say it's OK for gas but i don't think so.It comes as tablets & as a liquid mixture.The mixture can get really messy & tastes like Hawaiian poi.Take too much and it will constipate you.And if you take medications it will adsorb them