Recently, mesotherapy is frequently used for body contouring. But, there is a many controversy on the effect of mesotherapy for fat reduction, as well as it's complication tends to look over. So, we let you know the complicated case of the mesotherapy which we experienced. A 28-year-old woman after mesotherapy on her right lateral thigh was admitted to the hospital because of cellulitis and skin necrosis. The patient had a local injection on the both her lateral thigh for body contouring at local hospital. 2 days before hospitalization, we could see infection on her right lateral thigh. The infection finding was swelling, reddish to purple color change and bullae formation. As time goes by, skin necrosis and eschar formation took a place. The size of eschar was estimated about 12 × 10 cm. MRI was accomplished, and the cellulitis on the right hip ant thigh was found on the MRI. The eschar was surgically removed and wound bed was exposed to subcutaneous fatty layer. And then, split thickness skin graft taken from left lateral thigh was done successfully. The grafted skin was well taken without complication, as well as donor site was well healed. The mesotherapy for body contouring is tried by various method, but, the definite mechanism is not established and safe way of drug combination is not clear. For more safer procedure, more study about the way of drug combination and mechanism is needed.