Gingival overgrowth is an expression of over reaction to different kinds of local or systematic stimulations. The most frequently occurrences are slow stimulation caused by local factors such as calculus or plaques. Change of hormone or some specific medication may cause transformation of gingival connective tissue. An example as taking hypertension drugs like nifedipine may cause side effect as gingival overgrowth. This paper will focus on related literature reviews of the correlation between drug characteristic and gingival tissue. The cause of disease will also been clarified by our previous study which delineate the effect of nifedipine on immunological regulation (Th1/Th2) and its pharmacokinetics.