Continuous intravenous epoprostenol (prostacyclin) produces hemodynamic and symptomatic responses and improves survival in patients with severe primary pulmonary hypertension refractory to conventional medical therapy. However, it has been recently shown that short-term infusion of epoprostenol can produce pulmonary edema in pulmonary veno-occlusive disease, presumably because of increased pulmonary perfusion in the presence of downstream vascular obstruction. We describe two additional cases of pulmonary edema complicating continuous intravenous epoprostenol in patients displaying severe pulmonary hypertension and pulmonary capillary hemangiomatosis, a rare condition characterized by the proliferation of thin-walled microvessels in the alveolar walls. This report indicates that epoprostenol therapy should not be used in patients with severe pulmonary hypertension secondary to pulmonary capillary hemangiomatosis.