Epidemiologic studies indicate that episodic vasospasm of arterioles (Raynaud's phenomenon) is a common finding in the general population. The prevalence has been estimated at approximately 10%. Raynaud's phenomenon follows a benign course in most cases and may improve or even disappear in time. Occasionally, Raynaud's phenomenon may be induced by some drugs (beta-blockers, ergot, vinblastine...) or some occupations (pneumatic hammer operators, hand-arm vibration syndrome...) or may be a sign of connective tissue disease (systemic sclerosis, systemic lupus erythematosus, Sjögren's syndrome...). Several different physiologic mechanisms may be responsible for vasospasm: hyperactivity of the sympathetic nervous system and abnormal adrenergic receptor function appear to be most important. Calcium channel blockers have been studied extensively for the treatment of primary and secondary Raynaud's phenomenon. There have been shown to be particularly effective for inhibiting vascular responses evoked by alpha 2-adrenoceptor activity. Calcium channel blockers have been mostly effective in Raynaud's phenomenon.