碳氧血红蛋白为血红蛋白与一氧化碳分子的稳定化合物，当一氧化碳气体被生物吸入或在代谢过程中产生时形成。

血红蛋白有与一氧化碳结合的倾向，高于它和氧气的亲和力约240倍，当碳氧血红蛋白大量存在时就会妨碍氧气发送至身体各部分的过程，是为一氧化碳中毒。

碳氧血红蛋白的半衰期为4至6小时，解离速度较氧合血红蛋白慢3600倍。当一氧化碳中毒患者吸入混有4-5%二氧化碳的高浓度氧气时，体内的碳氧血红蛋白的半衰期会降至35至70分钟。患者若接受高压氧治疗时况会更佳，治疗过程中他会躺进注入高浓度氧气和加压至接近3atm（标准大气压）的舱中，协助身体吸收氧气。

Carboxyhemoglobin or carboxyhaemoglobin (symbol COHb or HbCO) is a stable complex of carbon monoxide and hemoglobin (Hb) that forms in red blood cells upon contact with carbon monoxide (CO). Large quantities of CO hinder the ability of Hb to deliver oxygen to the body, because carboxyhemoglobin forms more readily than does oxyhemoglobin (HbO₂). CO is produced in normal metabolism and is also a common chemical. Tobacco smoking (through carbon monoxide inhalation) raises the blood levels of COHb by a factor of several times from its normal concentrations.