Many persons associate fatigue and lassitude with iron deficiency and take extra iron "to be on the safe side". This is an unfortunate practice, as the early symptoms of iron deficiency anaemia and of hereditary iron overload (homozygous primary haemochromatosis) are similar. Primary haemochromatosis is considerably more prevalent than earlier believed. As many as 5 per 1,000 of the Norwegian population may have two mutated genes for haemochromatosis, while up to 15% may be carriers of a single mutated gene, and for these an extra intake of iron may be hazardous. The condition is highly underdiagnosed. In Norway at present, iron preparations of 60-100 mg are sold over the counter in pharmacies without prescription and often by self-service. However, no one should use iron tablets until iron deficiency and its cause has been ascertained. To avoid uncritical use of iron, iron preparations should be available only by doctor's prescription. Prolonged abuse of iron tablets may result in secondary haemochromatosis.