Parathyroid hormone plays an important role in calcium homeostasis. PTH is generally considered as a catabolic agent that promotes bone resorption. During 1930's, animal study has demonstrated promotion of bone formation by daily injection of parathyroid extract. The anabolic effect of PTH has been proved and used in treating osteoporosis now. In addition, increasing evidence suggest that PTH are beneficial in fracture healing process and implant placement. However, the effect of intermittent PTH in osseous defect, such as periodontal bony destruction or ridge defect, has not been determined. The PTH effect in osseous defect regeneration warrants further studies.