Cherry red coloration observed in fatalities is primarily caused by which gas?

• A. Hydrogen sulfide
• B. Nitric oxide
• C. Carbon monoxide
• D. Oxygen

Answer: (C)

Cherry red coloration in fatalities points to carbon monoxide poisoning. Carbon monoxide binds to hemoglobin with very high affinity, forming carboxyhemoglobin. This gives blood and tissues a bright red, cherry-like color, so the skin and cadaveric blood can appear distinctly red even though oxygen delivery to tissues is severely impaired. The lingering bright red livor mortis is a clue pointing to CO because the carboxyhemoglobin resists normal decolorization after death. Other gases produce different signs and do not produce this characteristic cherry-red hue, so hydrogen sulfide, nitric oxide, or pure oxygen do not fit the typical discoloration pattern seen with carbon monoxide.