Zoledronic acid is used in the treatment of a number of different problems which affect bones. In osteoporosis, zoledronic acid helps by preventing further loss of bone by helping to rebuild lost bone. It is also used for strengthening the bone in some cancers. In Paget's disease, zoledronic acid works on bones to make them stronger and helps to prevent bone thickening. There is some evidence that zoledronic acid may prevent breast cancer.