In Chile, hydrochlorothiazide is frequently prescribed as first line antihypertensive therapy. Among it’s well known adverse reactions are: electrolytic disorders, hyperuricemia, dyslipidemia, agranulocytosis and azotemia. Acute pulmonary edema is a rare and potentially lethal adverse effect. Only 50 cases have been reported since 1968. In this article, we discuss a case of a 70 year old woman who, one hour after the ingestion of hydrochlorotiazide, presented acute and progressive dyspnea. Her clinical and radiologic findings are compatible with non-cardiogenic acute pulmonary edema.