Six patients diagnosed as having polycythaemia vera had severe pruritus that persisted despite adequate haematological control. Iron supplementation was given when iron deficiency was noted in all six patients. The pruritus began to improve two to 10 days after the start of treatment and had completely disappeared after two to three weeks. In three patients the iron treatment was stopped because of unacceptably high haemoglobin concentrations; the pruritus recurred. Since chronic iron treatment may result in increases in red cell mass indiscriminate use of iron in patients with polycythaemia vera and pruritus is not advocated. Nevertheless, in patients with severe symptoms and evidence of iron deficiency treatment with iron, continuing for two to three weeks after the symptoms have abated, may be beneficial.