Bisphosphonates are synthetic analogue and have high affinity on bone remodeling site. Since they have a long half-reduction time, they accumulate at bone and act for a long time. They are widely used in osteo-porosis derived from imflammatory bowel disease or postmenopausal osteoporosis patient for bone mineral density improvement. In addition, they neutralize hypercalcemia owing to bone metastasis of malignancy. However, a jaw bone necrosis was recently reported in some patients who have taken bisphosphonates for a long time. It is called Bisphosphonate Related Osteonecrosis of Jaws (BRONJ). It can come spontaneous-ly, but more often after oral surgery including tooth extraction. In this case, a 80-year-old woman was treated with bisphosphonate (sodium alendronate) for 2 years to improve bone mineral density. She had her left lower second molar tooth extracted at local clinic. After extraction, she had inflammatory symptoms like a pain, a cheek swelling, and a discharge of pus. She was referred to our clinic for treatment. We treated meticulously from dressing to surgery. After following up about 1.5 years, the jaw lesion was successfully healed. So we report this case.