Alcohol is the most popular psychoactive drug in Western societies. It is categorized as a depressant that is absorbed through the stomach and small intestine and distributed via bloodstream. Alcohol is metabolized in the liver, though a small percentage is not broken down. Blood alcohol concentration depends on factors like weight, drinking rate, and genetics. Acute effects include impaired judgment and motor skills, while long-term heavy use can damage major organs and increase cancer risks. Treatment programs aim to address alcohol abuse and dependence.