Once the alcohol has crossed the bowel wall and entered the blood stream it has to pass through the liver before entering the general circulation and the rest of the body.
The liver is the body's detoxification plant and, along with the lungs and kidneys, is responsible for getting rid of alcohol.
The liver does this by breaking down the alcohol using enzymes contained within its cells and it can cope with a surprisingly heavy workload.
A typical person's liver will break down the equivalent of a unit of alcohol an hour and this can increase significantly in regular drinkers. This is one reason why a heavy drinker can appear comparatively sober after drinking enough to have the rest of us reeling.
Unfortunately, prolonged heavy drinking damages the liver. In the short term this damage may be reversible but, if not caught in time, the damage is permanent and may be life threatening.
A scarred and damaged liver (cirrhosis) is the main cause of death in very heavy drinkers - and untreatable - transplant is the only option.
Fortunately liver damage can be easily detected in blood tests and drinkers warned of future problems. Anyone who drinks more than the recommended limits is at risk of long-term liver damage.