Twenty-four patients with high microvascular permeability pulmonary edema were initially treated by means of conventional supportive therapy for 1-12 days. Continued deterioration was treated by predilutional hemofiltration and induced a dramatic improvement in 22/24 patients. Survival was 92%. Sieving coefficients for autacoids and middle molecular weight vasoactive peptides involved in the development of high microvascular permeability pulmonary edema were higher than 0.88 indicating that clearing from blood of these peptides during one pass through the hemofilter is similar to that obtained during one pass through the pulmonary normal microvasculature. Hemofiltration seems to be a significant breakthrough in the treatment of ARDS secondary to severe sepsis.