The alcohol found in alcoholic beverages is ethyl alcohol (ethanol). Alcohol is flammable (so flammable that it can be used as a fuel).
Alcohol is an amazing popular social phenomenon. Being legal, alcohol has become very assessable, cheap, and so has become socially acceptable. Alcohol is a drug and if invented today it would be a class ‘A’ prescription only drug as it is addictive and can cause physical and emotional damage.
Alcohol dissolves easily in water and so absorption within the body is effective.
After absorption, the alcohol enters the bloodstream. The blood carries the alcohol throughout the body. The alcohol from the blood then enters and dissolves inside each tissue of the body (except fat tissue, as alcohol cannot be dissolved in fat). Once inside the tissues, alcohol exerts its effects on the body. The observed effects depend directly on the blood alcohol concentration (BAC), which is related to the amount of alcohol consumed. Once in the bloodstream alcohol leaves the body in 3 ways:

• The kidneys eliminate about 5% through urine,
• The lungs exhale about 5%, and
• The liver breaks down the remaining alcohol into acetic acid and leaves in urine.

The liver can only eliminate 0.5 oz (15 ml) of alcohol per hour. So, it would take approximately one hour to eliminate the alcohol from a 12 oz (355 ml) can of beer.

Because the body uses water to expel alcohol it sends a message of thirst to the mouth that is telling us to consume water, this message can be misread and often results in the desire to take a further drink of alcohol! This increases the BAC, and acts on the nerve cells in the brain.

Alcohol interferes with communication between nerve cells and all other cells, suppressing the activities of excitatory nerve pathways and increasing the activities of inhibitory nerve pathways. The body responds to alcohol use, firstly in the form of euphoria – excitement – stupor – coma and with continued use death. Alcohol can cause death or sever physical problems whilst drinking large amounts very fast or with heavy prolong use, or due to sudden physical withdrawal.
The medulla, or brain stem, controls or influences all of the bodily functions that you do not have to think about, like breathing, heart rate, temperature and consciousness. As alcohol starts to influence upper centres in the medulla, such as the reticular formation, a person will start to feel sleepy and may eventually become unconscious as BAC increases. If the BAC gets high enough to influence the breathing, heart rate and temperature centres, a person will breathe slowly or stop breathing altogether, and both blood pressure and body temperature will fall. These conditions can be fatal.

What happens when I drink?

When alcohol is consumed, 20% is absorbed through the stomach and into the blood; the remaining 80% is absorbed through the small intestine. The body recognises alcohol as a poison and tries to eliminate it. Alcohol blocks a chemical called vasopression, this leads to the kidneys sending water to the bladder instead of it being reabsorbed in the body. The body needs water to help expel alcohol from the body but due to alcohol consumption the organs become dehydrated. Due to the fact that alcohol depresses & slows down the cortex functions of the brain, sleep is followed after heavy alcohol use. This means the body is not being re-hydrated, hence the organs become dehydrated. The organs try to make up for their water loss by stealing water from the brain, causing the brain to reduce in size; this pulls on the membranes in the skull, resulting in pain.  These symptoms are a familiar pattern in the sensation of ‘hangover’.
Frequent urination also expels salts & potassium that are necessary for nerve & muscle function; this can result in fatigue & nausea. Alcohol also expels glycogen that is stored in the liver; this results in further weakness, fatigue and poor coronation.