Short treatment courses of ACS have been shown to be of no demonstrable value in the treatment of ARDS. We gave two patients with persistant ARDS a trial of ACS after they demonstrated pulmonary uptake of 67Ga. Brief initial improvement disappeared with tapering of the ACS. A sustained course of ACS led to resolution of the ARDS in both patients. In all, ten patients with established ARDS were treated with sustained ACS over an 18-month period. The eight additional patients had uninterrupted courses of therapeutic ACS for greater than 21 days. The patients averaged 12 days of greater than 40 mg a day. At the time of treatment, all patients had established ARDS, meeting for at least 72 hours, criteria for the diagnosis of ARDS. A sustained course of ACS may be effective in the treatment of selected patients with established ARDS. Controlled studies of established ARDS are indicated to define the characteristics of these patients and their management.