In 20 - 60% of patients with Crohn’s disease bone demineralization is found, usually osteoporosis, but also osteoporosis with malatic features. The cause is the reduced calcium intake (loss of appetite, lactose intolerance and malabsorption), reduced vitamin D intake and corticoid therapy. Nowadays the diagnosis is facilitated by the use of densitometers (ultrasonic and DEXA) and markers of osteoresorption and new bone formation. In treatment in addition to calcium and vitamin D used for a long time, fluorides are administered (only as monofluorophosphate), nasal thyrocalcitonin and bisphosphonates of the third series (alendronate). In postmenopausal women also hormonal treatment can be used unless contraindicated. However, burdening of the bones with regular exercise is a necessity. For prevention adequate calcium and vitamin D intake is important, non-smoking, and exercise.

        Key words: M. Crohn, osteoporosis, densitometry, calcium, vitamin D, calcitonin, bisphosphonates.