Alcoholaemia means having ethanol circulating in the blood, the physiological basis for both the pleasures and the perils of drinking. After ingestion, alcohol absorbs rapidly through the stomach and small intestine, distributing through body water until its concentration, the blood alcohol concentration, reflects the balance between intake and the liver’s steady elimination rate of roughly one standard drink per hour. Effects scale with concentration: mild euphoria and lowered inhibition at low levels, impaired coordination and judgment as it rises, and potentially fatal respiratory depression at very high levels. Legal systems define driving limits in these terms, and food safety intersects through the handling of alcoholic beverages in production. Because food in the stomach slows absorption, drinking with meals produces lower, gentler peaks than drinking on an empty stomach.