Drug induced gingival overgrowth or enlargement manifests as abnormal growth of the gingiva due to an adverse drug reactions in patients treated with anticonvulsants, immunosuppressants, and calcium channel blockers. As gingival enlargement develops, it affects the normal oral hygiene practice and may interfere with masticatory functions. It gradually becomes a source of pain and the condition often leads to disfiguration. Within the group of patients that develop this unwanted effect, there appears to be variability in the extent and severity of the gingival changes. It would seem pertinent to identify and explore possible risk factors and relating them with the treatment plan. This book throws light on respective drugs and their association with gingiva, various mechanisms by which they cause enlargement and its treatment.