Gingival overgrowth as a side effect of medication taken for non-dental reasons is a very commonly occurring condition. The drugs most commonly associated with this condition are anticonvulsants like phenytoin, immunosuppressants like cyclosporin and antihypertensive drugs such as calcium channel blockers. Cyclosporin is a selective immunosuppressant which is sued to prevent rejection following organ transplant procedure. Various hypotheses have been considered in the pathogenesis of gingival overgrowth induced by cyclosporin. These include presence of different subsets of fibroblasts, role of pro-inflammatory cytokines and matrixmetalloproteinases. Plaque accumulation is also thought to play an important role in the pathogenesis of gingival overgrowth. More recent investigations have hypothesized the role of mast cells, androgens, growth factors etc,. in the pathogenesis of cyclosporin induced gingival overgrowth. However, there is no clear understanding of the proposed hypotheses and further research is essential to establish a clear pathogenesis of gingival overgrowth and provide better and more precise design for its prevention and treatment. The following review presents the pharmacodynamics and pharmacokinetics of cyclosporin, its role in prevention of graft rejection and in the pathogenesis of gingival overgrowth with various modalities available for the treatment of the same.