Serum and erythrocyte magnesium levels were screened between attacks in patients with migraine without aura (n=38) and with aura (n=6) and for comparison, in a group of patients suffering from chronic tension-type headache (n=25) as well as a group of control patients (n=19) at the Headache Unit, Citadelle University of Liege, Liege, Belgium. Serum magnesium levels were not significantly different between the four groups of patients, whereas magnesium levels in erythrocytes were significantly reduced in the group of migraineurs without aura (1.87) compared with those with aura (2.1), patients with tension-type headache (2.03) and the controls (2.12). Normal values in the laboratory ranged from 2-2.8 mmol/1 in erythrocytes. 
COMMENT. The correlation between magnesium levels and migraine pathophysiology is speculative. The possible importance of magnesium in migraine is suggested by the finding of reduced magnesium in white blood cells in women with premenstrual syndrome and headaches and the benefits of oral treatment with magnesium in premenstrual headaches. The authors hypothesize that the reduction in erythrocyte magnesium may be due to an abnormal regulation of intracellular magnesium in migraine patients.