The Heimlich maneuver should be used when a person shows signs of choking, such as inability to speak, difficulty breathing, or visible distress. In the context of toxicology, if a toxic substance causes physical blockage, or if the person is unable to cough up vomitus induced by a poison, the maneuver can be life-saving. However, it is crucial to first assess if the obstruction is mechanical and not due to swelling or other toxicological effects.
