Toxic epidermal necrolysis (TEN, Lyell’s syndrome) is a life-threatening disease of the epidermis and mucous membranes, appearing after exposure to certain drugs. The metabolites of drugs produced in keratinocytes activate the in situ synthesis of TNF-α followed by the process of apoptosis. The symptoms of TEN are erythema multiforme, flaccid bullae and epidermal necrosis followed by massive loss of epidermis of skin and mucosa as well. TEN mortality rate is between 30% to 40%. The therapy of TEN patients includes monitoring of fluid balance and the prevention of systemic infections. Specific therapy for TEN (corticosteroids, cyclosporin A, cyclophosphamide, iv immunoglobulin) is still controversial.