The aim of this study is to study the 2 months survival rate in patients with severe cirrhosis (Child-Pugh C) with pentoxifylline - an inhibitor of cytokine production. The 6 month mortality, the proportion of transplanted patients, the occurrence of complications (bacterial infection, renal failure, hepatic encephalopathy and gastrointestinal bleeding), plasma cytokine levels and fibrotest - a marker of fibrosis - will be also studied. This is a multicenter double blind randomized trial with a placebo.