Cyclosporin is a potent immunosuppressive drug and is frequently used in the therapy of autoimmune diseases, including systemic lupus erythematosus (SLE). Few large studies have been performed using this drug in SLE patients. However, small uncontrolled studies of patients with SLE have shown favourable results with a significant improvement in disease activity, a fall in anti ds DNA titres and proteinuria and an improvement in complement levels, leucopaenia and thrombocytopaenia. Interestingly, a consistent reduction in corticosteroid dosage often by as much as 50% is seen. Toxicity, especially with hypertension and renal impairment, occurs but usually reverses on dose reduction or the addition of an anti-hypertensive agent and is minimised by adherence to the strict monitoring guidelines. Large multi-centre randomised-controlled trials of the use of cyclosporin in SLE patients are underway and the results are eagerly awaited.