There are limited data linking benzodiazpine prescribing to road traffic accidents (RTA) and hip fractures but “epidemiological evidence for increased risks of several kinds of accidents with benzodiazepine use remains inconclusive” (1). METHODS: Case control study. Between June 1993 and October 1995, 4019 people were admitted with a fracture and 3186 people were admitted with trauma other than fracture from a fixed Tayside population of 319,465. Of these 19,304 people were dispensed benzodiazepines between June 1993 and October 1995 but had not been exposed in the previous 6 months. RESULTS: benzodiazepine users had an increased risk of admission for fractures (OR 1.9, 95% CI 1.7 to 2.1) and other trauma (OR 1.6, CI 1.4 to 1.8). The risk of fracture was markedly age related. The numbers needed to treat (NNT) for one associated admission with fracture was 95 (CI 79-120) for the whole population but the NNT fell from 199 (CI 111-918) at age 30-39 to 9 (CI 6-17) at age 90-99. The risk of other trauma was also age related but with a bimodal distribution. The NNT for one admission with other trauma was 163 (CI 126-234) for the whole population. At age 20-29 the NNT was 72 (CI 47-154), rising to 376 at age 40-49 and falling again to 61 (CI 38-167) at age 80-89. CONCLUSION: These results challenge the widely held belief that benzodiazepine drugs are safe with few serious side effects.