Alcohol consumption causes biphasic changes in blood pressure (BP) in Asians. The aim of the present study was to investigate the effects of repeated alcohol intake on BP and sodium metabolism. Fourteen Japanese males with hypertension (37-67 years old) were examined under standardized conditions (Na intake 120 mmol/day). After 1 week of alcohol restriction, the patients consumed a control drink with dinner for 3 days, 1 ml/kg of alcohol for the next 7 days, then the control drink for 3 days. Supine BP and heart rate were measured 5 times daily, and urinary excretion of water and sodium was determined throughout the study period. Average BP decreased initially, then returned to the baseline level during the alcohol period. Evening BP decreased significantly throughout the alcohol period, although the reduction was attenuated during the late phase. Morning and afternoon BP did not change significantly, but tended to be elevated during the late phase. Heart rate increased both in the morning and evening during the alcohol period. Urine volume did not change during the early phase, but increased significantly during the late phase. Urinary sodium excretion decreased initially, but increased during the middle phase of the alcohol period. In conclusion, BP decreases initially with sodium retention, then returns to the baseline level with restoration of sodium balance during repeated alcohol intake in Japanese males with hypertension. Sodium retention during the early phase appears to be the consequence of BP reduction and may contribute to the subsequent changes in BP.