Bisphosphonates are potent inhibitors of bone resorption and approved agents for both the prevention and treatment of osteoporosis. Many clinical studies have shown a consistent reduction in the risk of vertebral fractures with the use of these drugs, while others have shown a clear reduction in the risk of hip and other non-vertebral fractures. The bisphosphonates are divided into three generations based on their potency and chemical structure. In general, as a substance group they are well tolerated and, when applied correctly, the toxicity is low. Alternative dosages, e.g. monthly, three times a month or yearly as an oral drug or i.v. would probably improve patient compliance. Clinical studies have also shown the safety and effectiveness of bisphosphonates over a period of 3-7 years.