This study is a randomized, double-blind, placebo-controlled, multicenter study of rPAF-AH compared to placebo in patients with severe sepsis. Eligible patients from investigative sites located throughout the United States and other countries will be randomized to receive either rPAF-AH or placebo administered daily for five consecutive days by intravenous (IV) infusion. All patients will be evaluated for safety and efficacy endpoints over 28 days. A follow-up evaluation will occur approximately 6 months after Day 28 to assess functional status and quality of life.