Which symptom is associated with copper poisoning?

The symptom associated with copper poisoning is the presence of blue or green vomitus. This distinctive coloration occurs due to the chemical reaction between copper salts and stomach acids, resulting in the formation of copper compounds that can give vomit a blue or green hue.

Copper is a heavy metal that, when ingested in excessive amounts, can lead to gastrointestinal irritation and toxicity. Symptoms might include nausea, abdominal pain, and the aforementioned colored vomit. Recognizing this specific symptom can help in identifying copper poisoning and prompt timely medical intervention.

The other options, while they may suggest various health issues, do not specifically indicate copper poisoning. For instance, severe headaches could be symptomatic of many conditions, skin rashes can be caused by a myriad of allergens or irritants, and a persistent cough often points to respiratory issues. None of these are characteristic indicators of copper toxicity.