Four patients with variegate porphyria (VP) were treated with repeated haem arginate infusions daily for 4 days and then weekly for 4 weeks. After the initial four daily doses of haem arginate (haem 3 mg/kg), the excretion of faecal protoporphyrin (mean 579 nmol/g dry wt) fell to an almost normal level (mean 123 nmol/g dry wt), and that of coproporphyrin (mean 162 nmol/g dry wt) to the normal level (mean 21 nmol/g dry wt) in all patients. However, during the period of the four weekly infusions of haem the excretion of porphyrins increased almost to the pretreatment level. Phototesting showed no changes in the photoreactivity of the skin, and no improvement in skin lesions was seen during the treatment. Except for one case of thrombophlebitis no side-effects occurred. In a child with homozygous VP, four daily infusions of haem arginate (2 mg/kg) normalized the faecal protoporphyrin content, but had no effect on the increased erythrocyte protoporphyrin concentration.