What outcome indicates that the administration of activated charcoal has been effective in treating a poisoning?

The administration of activated charcoal is aimed at reducing the absorption of certain poisons in the gastrointestinal tract. When activated charcoal is effective, it binds to the toxic substance and prevents its further absorption into the bloodstream. This direct action on the poison is the primary goal of using activated charcoal and is the most straightforward outcome that demonstrates its effectiveness.

While stabilization of vital signs can be a positive outcome, it does not specifically indicate that the activated charcoal has worked to reduce the absorption of the poison. Similarly, nausea can occur for various reasons, including the poisoning itself, and may not reflect the efficacy of the treatment. The ability to talk coherently may suggest improvement in the patient's mental status but again does not directly correlate with the success of the charcoal treatment in terms of toxic absorption. Thus, the correct answer focuses directly on the mechanism of action of activated charcoal in poison management.