At moderate doses, alcohol can cause drowsiness, slowed reflexes and uncoordination. Alcohol is absorbed from all parts of the gastrointestinal tract. Most of the alcohol enters the bloodstream from the stomach and small intestine. It readily passes from the blood into nearly every tissue in the body, including the brain. The presence of food in the stomach slows the rate of absorption.
Interestingly men are more active stomach metabolizers than women.
While no one would get drunk from the alcohol in one or two teaspoons of cough syrup, liver and stomach enzymes cannot deactivate large amounts of alcohol consumed at one time. Alcoholic drinks, including beer cause the amount of alcohol in the blood to rise. Excessive drinking may lead to vomiting and other unpleasant toxic effects. These symptoms are part of the automatic defense systems of the body which are activated to prevent more alcohol from being absorbed. When drinking stops, the liver enzymes will eventually convert the excess alcohol into less harmful substances.