The purpose of this study is to confirm the efficacy and safety of sivelestat in patients with acute lung injury associated with systemic inflammatory response syndrome. The results will be compared to the study with conventional treatment without sivelestat.

Inclusion Criteria:

1. Patients with systemic inflammatory response syndrome (SIRS)
2. Patients with acute lung injury (ALI) assessed using the criteria specified by the American-European Consensus Conference
3. Within 72 hours of onset of lung injury
4. Other inclusion criteria as specified in the protocol

Exclusion Criteria:

1. Already administrated Sivelestat before enrollment in the study
2. Neuromuscular disease that impairs spontaneous ventilation
3. Severe central nervous system disease
4. Bone marrow transplant
5. Lung transplant
6. Severe chronic liver disease
7. Neutropenia (neutrophil count: below 1000/mm3)
8. Other exclusion criteria as specified in the protocol