Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are acute mucocutaneous diseases which become manifest as typical skin and mucous membrane lesions. It is etiologically a multi-factorial disease. The authors describe two case reports of patients with Stevens-Johnson syndrome and toxic epidermal necrolysis. A combined anti-epileptic treatment with lamotrigin, valproate and clonazepam was probably closely associated with the development of TEN in the first patient. In the second patient mycoplasma was the triggering moment in the development of SJS. An early diagnosis and correct therapy favorably influence the development of complications and mortality in the patients.