I t is well recognized that alcohol is a precipitating factor of angina1 attacks in patients with variant angina. 1,2 Angina1 attacks in some patients with variant angina are closely related to alcohol ingestion.2 The attacks usually occur several hours after alcohol ingestion. Therefore, it is postulated that angina may be induced by a major metabolite, acetaldehyde, rather than the direct action of alcohol.2 Catecholamines released by acetaldehyde may induce coronary spasm through a-adrenergic receptors that are present in large coronary arteries. However, the precise mechanisms responsible for the occurrence of coronary spasm by the ingestion of alcohol have not been elucidated fully. Recent studies indicated that magnesium (Mg) deficiency may be involved in the pathogenesis of coronary spasm. 3,4 Because urinary Mg excretion is augmented by alcohol drinking,5 Mg deficiency may be responsible for angina1 attacks related to alcohol ingestion. The present study was designed to examine: (1) whether there is Mg deficiency in patients with alcoholinduced variant angina, and (2) whether intravenously administered Mg is effective in suppressing alcohol-induced variant angina. This study comprised 2 separate protocols. Protocol I included 21 patients with variant angina, with or with-