Cyclosporine is a relatively new immunosuppressive agent which has been used successfully to prevent organ transplant rejection, to treat type‐I diabetes mellitus as well as several other autoimmune disorders. It is anticipated that the therapeutic use of cyclosporine will progressively increase in the future to include the treatment of numerous other disorders. As its clinical use broadens, more health professionals will need to become familiar with the beneficial effects as well as some of the undesirable side‐effects of cyclosporine therapy. Two side‐effects of the drug which are of interest to the periodontist are gingival hyperplasia and transient perioral hyperaesthesia. It is anticipated that the dental profession, particularly periodontists, will be called upon to help prevent, control or treat these side effects. The purpose of this paper is to familiarize the periodontist with cyclosporine and to discuss its anticipated impact on the practice of periodontics.