Activated charcoal is most effective when given within 1 hour of ingestion.

• A. True
• B. False
• C. Only within 3 hours
• D. Only in hospital

Answer: (A)

Activated charcoal adsorbs toxins in the gastrointestinal tract, preventing their absorption into the bloodstream. Its ability to bind is highest when the toxin is still in the stomach or upper small intestine, so giving it as soon as possible after ingestion captures more toxin before absorption begins. The benefit diminishes as time passes and the toxin moves further along the GI tract or is absorbed, making the one-hour window the most reliable period for effectiveness. This is why the statement is true. In practice, charcoal is used when there are no airway or contraindication issues and it’s within a suitable timeframe; its usefulness decreases beyond that window and it isn’t effective for certain substances like caustics or metals.