Stevens Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe acute mucocutaneous diseases. The early stage of the disease is characterized by red-purple maculopapular eruptions. Then epidermal separation occurs and vesicles and bullae are formed. Inflammatory changes including purulent conjunctivitis, erosion, ulcer and crusts may be observed in the eye, mouth, nose, pharynx, esophagus, trachea, gastrointestinal tract, urinary tract and genital mucosae. Life-threatening bleeding and infections may be observed as a result of these changes. The rates of severe complications or sequelae secondary to SJS and TEN are higher in patients with mucosal and ophthalmic involvement. The SJS and TEN are considered the same disease process, and the distinction is made based on body surface area involvement. The SJS is characterized by less than 10% of the body surface area of epidermal detachment, and TEN by more than 30%. Various etiologic factors have been implicated as causes of SJS-TEN. These include infection, vaccination, drugs, systemic diseases, physical agents, and food. Drugs are the most commonly blamed. It has been reported that SJS-TEN is strongly associated with the specific variants of the human leukocyte antigen HLA-A and HLA-B genes. There is still no consensus on a definite treatment method for SJS-TEN. Systemic steroids and IVIG are used most frequently in medical treatment and treatment options including cyclosporine, plasmapheresis and hemodialysis are required more rarely.