The peripheral vasospastic symptoms associated with Raynaud's disease continue to be an unsolved clinical problem. Hexopal (Hexanicotinate inositol) has shown promise in uncontrolled studies and its use in patients with Raynaud's disease may reduce such vasospasm. This study examines the effects of 4 g/day of Hexopal or placebo, during cold weather, in 23 patients with primary Raynaud's disease. The Hexopal group felt subjectively better and had demonstrably shorter and fewer attacks of vasospasm during the trial period. Serum biochemistry and rheology was not significantly different between the two groups. Although the mechanism of action remains unclear Hexopal is safe and is effective in reducing the vasospasm of primary Raynaud's disease during the winter months.