When used to treat poisoning or an overdose, activated charcoal is usually safe, but it needs to be administered only in a health care facility.
Side effects are more likely when it is used on a long-term basis to treat conditions like excess gas. When you take it by mouth, activated charcoal can cause:
In more serious cases, it can cause gastrointestinal blockages.
- Black stools
- Black tongue
- Vomiting or diarrhea
- Constipation