Aggressive non-Hodgkin's lymphoma is difficult to handle once it relapses or becomes refractory to chemotherapy. Various second or third line chemotherapies, which are called salvage chemotherapy, were developed without promising results. Improvement in efficacy by adding relatively new agent, rituximab, to chemotherapy is now widely accepted in non-Hodgkin's lymphoma. This study will test the safety and efficacy of adding rituximab to existing salvage chemotherapy, ESHAP (R-ESHAP). Our aim is also to proceed to high-dose chemotherapy with autologous hematopoietic stem cell transplantation after successful R-ESHAP therapy.