We report on the progress of a new modified method of phlebotomy, erythrocytapheresis, as a means of fast therapeutic removal of erythrocytes from the circulation. We performed erythrocytapheresis in 65 patients. In 18 patients with central venous thrombosis of the eye, the beneficial effect of this procedure proved superior to the traditional approach. In 29 patients with primary or secondary polycythemia, hemoglobin, hematocrit, and blood viscosity could be lowered drastically for up to 11 months by a single erythrocytapheresis. We performed erythrocytapheresis in an effort to deplete the iron stores in patients with hemochromatosis (14 cases) and in patients with porphyria cutanea tarda (4 cases). Several consecutive erythrocytaphereses were necessary, however, to even slightly lower the amounts of stored iron as measured by serum iron, iron-binding capacity, and serum ferritin in these patients. The intervals between treatment were 2 to 11 months, thus much longer than the intervals between blood-lettings. We did not observe any adverse side effects. There was no significant influence on the clotting system, and no reactive thrombocytosis as described after phlebotomies.