While cyclosporin has an established role in the treatment of rheumatoid arthritis there is concern about adverse effects, mainly related to renal function. With new interest being generated in cyclosporin combination therapy, and the availability of a new form of cyclosporin (cyclosporin microemulsion), focus on adverse effects and drug interactions of this compound remains important. Over the years, rheumatologists have been aware of these adverse effects and consensus meetings have resulted in guidelines for the use of cyclosporin. If these guidelines are followed, structural renal damage can be minimal. Cyclosporin should be started at a low dose and titrated against the highest acceptable increase in serum creatinine, that is, a 30% increase over the pretreatment value. At present, there is no evidence that cyclosporin in combination with other antirheumatics leads to increased toxicity. With regard to long term unwanted effects, neither the pattern nor the risk of malignancies associated with the use of cyclosporin seems to differ from other antirheumatics. The place of cyclosporin in the treatment of rheumatoid arthritis seems to be established. The most promising results will come from early rheumatoid arthritis combination studies involving cyclosporin with other antirheumatics, especially methotrexate.