The efficiency and tolerability of using a new osmotic diuretic, i.e. polyosm (a solution of polyethylene oxide 400 for the intravenous administration), was studied in patients with edematous maculopathy of different geneses. The drop-by-drop introduction of polyosm, 200 ml (the dose amounted to 0.8-1 g/kg in terms of polyethylene oxide 400), one per day and during 3 days, proved the efficiency of the preparation as a corrector of edematous maculopathy, which was confirmed by an involution of the eye-tissue edema, reduced sizes of the central scotoma, and by an improved visual acuity. The tolerability of the course-based administration of polyosm by patients was found to be good and satisfactory. No negative impact produced by the preparation on the indices of central hemodynamics was detected; the hypotensive effect of polyosm was found, as a normalized level of the systolic and diastolic pressure, only in patients with an originally high arterial pressure. Hypokalemia was, after the course-based use of polyosm, of a moderate nature.