Answer: So as soon as you drink alcohol, it begins to be absorbed into your blood. A small amount can even be absorbed through the tissues in your mouth while you’re drinking. But alcohol is primarily absorbed into your blood from your stomach. As the alcohol is absorbed into your blood, that’s when it has the physical effect on your body. It reaches your brain and affects your central nervous system, which results in the effects that you see when someone has been drinking alcohol. The amount that you have in your blood can then be tested by either drawing blood and testing your blood for alcohol. The alcohol content can also be measured by measuring exhaled deep lung air and checking to see how much alcohol is in that air. Because alcohol is very volatile—meaning it likes to be a gas and go into the air—it can be measured in air more easily than other drugs which are not as volatile. And then honestly, the other side of blood alcohol content is that it will fall, it will come down as your body eliminates alcohol and processes it. So you have kind of a bell curve look with alcohol absorption and then elimination.