亚甲蓝是一种解毒药，为深绿色、有铜光的柱状结晶或结晶性粉末；无臭。高浓度时直接使血红蛋白氧化为高铁血红蛋白。低浓度时，在还原型辅酶I脱氢酶（NADPH）作用下，还原成为还原型亚甲蓝，能将高铁还原型蛋白还原为血红蛋白。在体内借酶的参与，起着递氢体作用。不同剂量对血红蛋白效应不同，大剂量（或高浓度）治疗氰化物中毒。本药静脉注射作用迅速，并还原为无色亚甲蓝，在6d内74%由尿排出，部分从胆汁排出。肾功能不良者，血浓度可升高。本药主要损害胃肠道、心血管和中枢神经系统、肾脏等。亚甲蓝不能做皮下、肌内和椎管内注射。椎管内注射易引起中枢神经系统永久性器质性损害，皮下注射易产生局部坏死性脓肿。

The patient had received 200 mg methylene blue (MB), i.v., for treatment of septic shock 90 min prior to death. Analysis of tissue samples by liquid extraction and liquid chromatography coupled to tandem mass spectrometry demonstrated different concentrations of MB and its metabolites azure A and B in the heart, lungs, kidneys, and liver. Our findings clearly demonstrate the relation of MB administration and organ discolouration at autopsy and shed a new light on MB distribution and accumulation in septic shock.