We describe a case of a patient presenting repeated episodes of sudden-onset pulmonary edema each occurring immediately after the ingestion of hydrochlorothiazide. The close temporal relationship between the ingestion of hydrochlorothiazide and the onset of symptoms together with the rapid and full clinical recovery after the interruption of therapy, allowed the diagnosis of drug-induced pulmonary edema and a possible anaphylactoid hypotension. The initially low white blood cell count, associated with hemoconcentration, and the increase in white blood cells during the following 24 hours, is consistent with the hypothesis of intrapulmonary sequestration of granulocytes causing pulmonary edema. The pathogenesis and the cause of the increased pulmonary sensitivity are reviewed and discussed.