Septic shock occurs in 6 % of paediatric cancer patients with neutropenia and fever. The mortality of the septic shock is 40 % in BMT patients and 5 % in others. One third of paediatric ARDS cases affect immunocompromised individuals with a total mortality of 45 % and 80 % after BMT. Septic shock is caused by gram-negative bacteria in more than 75 %. ARDS is due to pneumonia in more than 50 %, sepsis in about 25 %. This article provides the recommendations of the Infectious Diseases Working Party of the German Society for Pediatric Infectious Diseases (DGPI) and the German Society for Pediatric Hematology/Oncology (GPOH) for treatment of septic shock and ARDS. Therapy of septic shock includes early antibiotic therapy and volume expansion (> or = 40 ml/kg initially). Refractory shock requires vasopressors (noradrenaline), followed by a judicious circulatory management. Hydrocortisone is indicated in patients with high probability of adrenal insufficiency. Mainstay of ARDS therapy is ventilation with sufficient end-expiratory pressure (PEEP) to prevent loss of functional residual capacity and with limited tidal volumes (< or = 6 ml/kg) and limited inspiratory pressure (< 35 cm H(2)O) respectively, to minimize ventilator induced lung injury. Volume therapy consists of maintenance of sufficient preload to counteract the impaired venous return, induced by positive pressure ventilation. Diuretics and eventually veno-venous haemofiltration are used to reduce free lung water. Surfactant application may be considered in severe cases. Steroids are indicated in pneumocystis carinii pneumonia and in engraftment pneumonitis.