Chocolate-colored postmortem lividity is indicative of which type of poisoning?

Chocolate-colored postmortem lividity is specifically indicative of nitrite poisoning. When nitrites are ingested or introduced into the bloodstream, they oxidize hemoglobin, resulting in the formation of methemoglobin. This altered form of hemoglobin does not transport oxygen effectively but gives the blood a characteristic chocolate-brown color. As the body undergoes decomposition, livor mortis (postmortem lividity) sets in, and the presence of nitrites within the blood can manifest as this unusual coloration.

In contrast, other types of poisoning do not result in similar changes to blood coloration in the context of postmortem lividity. For example, phosphate poisoning primarily impacts the nervous system and can lead to symptoms like respiratory failure but does not alter blood color. Arsenate poisoning is associated with gastrointestinal symptoms and can lead to asphyxiation but does not produce chocolate-colored lividity. Mercury poisoning typically affects the kidneys, gastrointestinal tract, and nervous system, leading to other clinical signs, but again, does not create the same dramatic change in blood color observed with nitrites.