Toxic epidermal necrolysis is a rare, severe cutaneous reaction, mostly caused by drugs. It affects the skin and mucous membranes, with involvement of more than 30% of body surface. We describe the case of a young woman, previously healthy, who developed skin detachment of more than 90% of the body surface 15 days after being administered lansoprazole for peptic disease. The treatment consisted in discontinuation of the drug involved and early administration of intravenous human immunoglobulin, which led to a satisfactory outcome of the case, substantiating the impact of early diagnosis and treatment on the morbidity and mortality of these patients.