Beagles and rats were subjected to hemorrhage regimens that induced the pulmonary complex of the Acute Respiratory Distress Syndrome (ARDS) in 6:6 dogs and 7:8 rats. Pretreatment with diphenylhydantoin (DPH), 5 mg/kg 1-2 hours preceding hemorrhage, resulted in complete prevention of the lung lesions in 8:8 dogs. (P smaller than 0.005). It also provided significant (P smaller than 0.01) protection to 8:11 rats. We offer this as circumstantial evidence that the ARDS has a centrineurogenic etiology.