Clinical experience with five patients exposed to phosgene is described. The treatment of phosgene poisoning was focused upon the presenting problem, pulmonary edema. Arterial hypoxemia was treated with a face mask with 10 cm CPAP with the FiO2 adjusted as needed or with a volume ventilator with controlled ventilation. Ventilation was controlled to reduce the work of breathing. Metabolic acidosis was treated with NaCHO3 to produce a normal pH. A vigorous program of diuresis was used to treat the pulmonary edema. Lasix was administered to produce a negative fluid balance while maintaining a good urinary output. The negative fluid balance correlated well with reduced oxygen requirements.