The anti-fracture efficacy of sodium fluoride (NaF) was evaluated in 84 postmenopausal white women with spinal osteoporosis. The dose of NaF used was 75 mg/day and all patients in this prospective, randomized, double-blind, placebo-controlled clinical trial received calcium supplements (carbonate salt) 1500 mg/day in addition to participating in a structured physical therapy program. For each of the outcome measures (change in stature, change in cortical bone mass in the forearm and development of new vertebral fractures determined by change in vertebral morphometry and by scintigraphy) there was no significant difference between the fluoride or placebo treated groups. Side effects, predominantly gastrointestinal symptoms and the development of the painful lower extremity syndrome, occurred significantly more frequently in the fluoride group (P<0.05). peripheral="" fractures="" were="" not="" more="" frequent="" in="" the="" fluoride="" group.="" we="" conclude="" that,="" in="" the="" dose="" and="" manner="" used="" in="" this="" study,="" naf="" is="" no="" more="" effective="" than="" placebo="" in="" retarding="" the="" progression="" of="" spinal="" osteoporosis.="" there="" is="" no="" role="" for="" naf="" in="" the="" treatment="" of="" osteoporosis="" outside="" the="" confines="" of="" clinical="">