The 29-year-old woman was taken to MC Erebouni from another medical center - with Lyell's syndrome, bilateral pneumonia, in extremely serious condition and was immediately hospitalized in intensive care unit. His condition rapidly deteriorated after receiving antibiotic treatment for pneumonia a few days ago, which caused severe drug allergy -Lyell's syndrome. The head of the Intensive Care Unit Dr. Armen Muradyan and the head of the Allergology Service Dr.Kristina Jamalyan immediately focused on treating the patient. The treatment strategy was carried out in two parallel directions: it was necessary to treat pneumonia and drug allergy simultaneously, which was one of the main treatment complexities. For the treatment of pneumonia, it was necessary to choose such antibiotics that will not aggravate the drug allergy again. The patient has never had a drug allergy before and carefully studied the medicine that did not cause allergic reactions. Lyell's syndrome is a severe allergic disease that causes necrosis of the skin, exfoliates the skin and mucous membranes, including internal organs. The mortality rate is quite high-30 %. During 10 days in the Intensive Care Unit, doctors fought for patient`s life, and after the patient's condition was stabilized, he received treatment in the Allergology Service for another 10 days. Thanks to serious professional work, the young woman's life was saved. She was discharged from the hospital in satisfactory condition.