Cherry red postmortem lividity is associated with which substance?

Cherry red postmortem lividity is a distinctive manifestation frequently associated with carbon monoxide poisoning. When carbon monoxide binds to hemoglobin in the blood, it forms carboxyhemoglobin, which gives the blood a bright red color. Upon death, this coloration can be observed in the dependent parts of the body, leading to the characteristic cherry red or pink appearance of the livor mortis (postmortem hypostasis) in individuals who have succumbed to carbon monoxide exposure.

The other substances listed do not produce the same effect in terms of livor mortis. Oxygen does not cause any discoloration that would lead to cherry red lividity; it is essential for aerobic metabolism but does not produce coloration effects in the blood postmortem. Hydrogen sulfide, while toxic, tends to create a more ashen or dark discoloration due to its effects on blood and tissue metabolism. Cyanide, another potent poison, can cause a range of symptoms and effects but does not result in the cherry red lividity characteristic of carbon monoxide poisoning. Therefore, the entity most specifically linked to cherry red postmortem lividity is carbon monoxide.