Raynaud's phenomenon may cause severe digital pain and functional disability, particularly in patients with underlying connective tissue diseases. The pathophysiology of Raynaud's phenomenon is varied, but digital ischemia is an essential element. Because calcium channel blockers cause arteriolar vasodilation and an increase in peripheral blood flow, they have been used to treat patients with Raynaud's phenomenon in several prospective, randomized, double-blind, placebo-controlled trials. Verapamil was ineffective in low doses, but both nifedipine and diltiazem produced subjective improvement. In placebo-controlled studies with nifedipine, the frequency of vasospastic episodes per two weeks decreased from 14.7 episodes during placebo therapy to 10.8 during nifedipine therapy (p less than 0.05). This response was more pronounced in patients without underlying vascular disease. Moderate or marked subjective improvement occurred in 60 percent of the patients receiving nifedipine and in only 13 percent of patients receiving placebo. Adverse effects were mild. It is concluded that nifedipine is an effective short-term therapy for most patients with Raynaud's phenomenon.