Iatrogenic complications, sometimes fatal, are not uncommon in medical practice. They are especially common in emergency hospitals, where the time of clinical examination and treatment of patients is always limited due to the severity and speed of the disease. The problem of iatrogenic diseases is most concerned with clinical toxicology. The potential danger of the development of acute poisoning is represented by about 6 thousand xenobiotics synthesized annually in the world. Various chemical compounds become a threat to life as a result of environmental, technological or transport disasters, suicidal or criminal actions. The extreme variety of nosological types of chemical diseases (more than 500) creates a constant problem of diagnosis and treatment of acute poisoning with "unknown poison." Due to the multitropic toxicity of many chemicals in the clinical picture of these diseases, most of the pathological syndromes observed in emergency therapy can be found.