Where Does Alcohol Go in the Body? Alcohol leaves the capillaries to enter tissues, including the brain As ethanol circulates throughout the bloodstream, the concentration gradient is in the direction that favors movement of ethanol from the capillaries through interstitial spaces and into cells of different organs. The loosely packed endothelial cells and the fenestrae allow ethanol to move easily out of the capillaries. There is an exception to the “leaky” capillaries—in the brain, the capillaries do not have fenestrae and the endothelial cells are tightly packed together. This construction helps to form a barrier (the “blood-brain-barrier”) to drugs and other molecules that are charged or polar, preventing them from entering the brain itself. Because alcohol is slightly lipophilic, it can still diffuse across the brain endothelial cell membrane, with the concentration gradient to get into (or out of) the brain. In the brain, alcohol interferes with the brain cell function to cause intoxication.