Psoriasis is a chronic condition that shows variability in phenotype and severity. The disease can seriously compromise patients' quality of life, regardless of disease extent. Systemic treatment is indicated when lesional burden is extensive and/or frequently relapsing, and when quality of life is severely altered. Furthermore, surveys have indicated that patients are dissatisfied with their current topical or phototherapy. The efficacy of ciclosporin in the treatment of psoriasis is well established. However, widespread use of this drug has been limited by concerns over adverse effects, such as renal impairment, hypertension and the potential risk of malignancy. Data from many clinical trials designed to examine the efficacy and safety of long-term continuous and intermittent short-course (< 12 weeks) therapy are now available. Information from these studies has aided dermatologists in developing treatment guidelines. Intermittent short-course therapy is well tolerated, safe, and highly effective in sustaining disease control and promoting quality of life. Long-term continuous ciclosporin therapy may be useful in some patients with refractory psoriasis. If treatment guidelines are followed, the risk of nephrotoxicity and hypertension is low. Ciclosporin therapy is associated with an increased risk of non-melanoma skin cancer (mainly squamous cell carcinoma) when patients have been previously exposed to psoralen-ultraviolet A (PUVA). The incidence of non-skin malignancy shows no significant difference to that observed in the general population.