Alcohol use has been identified as a risk factor for the development of osteoporosis. Eight male Wistar rats at two months of age were alcoho-fed (7.6 g 95 % ethanol/kg b.w. per day) to evaluate the effects of long-term administration (three months) of alcohol in drinking water. We have used a dose which is considered to be comparable to a dose of 1 liter of wine or 2.5 liters of 12(°) beer used in male adults daily. The bones were tested mechanically by a three-point bending test in a Mini Bionix (MTS) testing system. The bones from alcohol-fed rats were characterized by a reduction in bone density as well as in ash, calcium and phosphate content. In alcohol-fed rats the reduction in bone mineral density (10 %) was reflected by about 12 % reduction of mechanical strength of femur (158+/-5.5 vs. 178+/-3.2 N/mm(2)). Alcohol significantly altered femoral cortical thickness. In our experiment alcohol itself did not exert any antiandrogenic effect and it did not produce changes in the weight of seminal vesicles. Liver function test (GGT, ALP, AST) did not differ between alcohol-fed rats and control rats. Alcohol-induced bone loss is associated with increased bone resorption and decreased bone formation. These results document the efficacy of alcohol at the dose of 7.6 g 95 % ethanol/kg b.w. to cause bone loss and loss of bone mechanical strength in intact rats. The results of the present study may be interpreted as supporting the hypothesis of alcohol as a risk factor for osteoporosis.