The authors describe the čase of nitrobenzene poisoning in a 4.5-year boy. The toxicity of nitrobenzene consists in development of methemoglobinaemia with subsequent hypoxia. Acute symptomatology includes cyanosis, dyspnoea and headache. In severe cases there are also convulsions and death. Chronic symptomatology includes the failure of liver and kidneys and anaemia. The treatment includes the use of toluidine blue as an antidote, which bears several risks. The pathophysiology of occurrence and treatment of the nitrobenzene poisoning is discussed.

        Key words: poisoning, nitrobenzene, methemoglobinaemia