While serving in the Southwest Pacific area 2 soldiers developed asthmatic symptoms, lassitude, loss of wt., marked leukocytosis and marked eosinophilia of the blood as described by Weingarten. Their symptoms continued after their return to the U. S. Exhaustive clinical and laboratory studies failed to reveal the etiology of the syndrome. Both cases responded to arsenical therapy. Intravenous arsenical treatment seemed more effective than oral treatment.