What is Alcohol and What Does it Do to the Human Body?

What is Alcohol?

Alcohol, in a basic sense, is an organic compound. It is described scientifically as comprised of naturally occurring elements with carbon atoms. Alcohol is an intoxicating substance. It produces effects when ingested into the human body. There are various types of alcohol. What I deal with in my job as a defense attorney is ethanol. Ethanol is molecularly described as H3C2-OH. The OH group at the end of the group of molecules is what makes the compound an alcohol.

Ethanol is beverage alcohol. It is the primary ingredient in beer, wine, liquor, etc. The process of alcohol production starts with the fermentation process. This is a type of decomposition in which the sugars in fruit, grains, etc. combine with yeast to produce ethanol. Ethanol can also be created through the distillation process. Distilled spirits include rum, whiskey, gin, vodka, etc. The alcohol concentration of distilled spirits varies. A can of beer, a glass of wine, and a shot of liquor are roughly the same in terms of alcohol content.

Alcohol is a central nervous system depressant. Alcohol enters into a person’s central nervous system by drinking it. The first step towards absorption is the stomach and the movement of alcohol into the blood. It should be noted that alcohol doesn’t have to be digested in order to pass from the stomach to the blood. It can pass directly through the walls of the stomach. Under the right circumstances, absorption of alcohol can take place very quickly.

Alcohol’s Impact on the Body

When alcohol enters into an empty stomach, roughly 80 percent will go through the base of the stomach and end up in the small intestine. Here, it will be absorbed into the blood. The human body doesn’t need to digest the alcohol before allowing it into the bloodstream. The small intestine will be ready to take the alcohol as soon as it hits the stomach.

Food’s Impact

The intake of food does come into play in DUI cases. Food has to be at least partially digested before it passes into the small intestine. When the brain perceives food to be in the stomach, it tells a muscle located at the base of the stomach to constrict. It then cuts off the passage to the small intestine. This muscle is known medically as the pylorus, or pyloric valve. As long as it remains constricted, very little will move out of the stomach to the small intestine. If any alcohol is located in the stomach along with food, the alcohol will be trapped behind the pylorus. Some of the alcohol that remains trapped in the stomach will begin to chemically break down. This happens before it ever gets into the bloodstream.

Over time, the digestive process continues, the pylorus eventually will relax, and some of the alcohol and food will pass through. But, the effect of the stress of the arrest is to slow the absorption significantly. Here is where the human body can work against the DUI driver. When a person is pulled over, the experience is stressful on the mind and body. When a person experiences stress, the body goes into a state of preparation for flight or fight. The body shuts down other immediately unnecessary bodily functions. Since digestion takes a large amount of energy to occur, the digestive system shuts down quickly. When this happens, the body stops processing the contents of the driver’s stomach, and two things happen.

Alcohol in the Body

First, a buildup of ethanol vapor will enter the airway and come out when a person talks. This causes an officer to smell more alcohol. Secondly, the alcohol won’t get processed at that time. Eventually, when the driver is brought to the station, and finally relaxes from the state of stress, the body then reopens that value. It floods the system with the contents of the stomach to replace that energy burned off in the stressful state.

What happens then? The ethanol hits the bloodstream hardest around the time the breath or blood test is given. The measurement likely doesn’t match what was in the breath or blood at the time of driving, but the police and prosecution do not care about this likelihood. Alcohol normally gets into the blood slowly, and the body will continue to process and eliminate the alcohol that manages to get in. The BAC (blood alcohol concentration) of a drinker rises faster if they are drinking alcohol on an empty stomach.

Alcohol in Bloodstream

Once alcohol moves from the stomach into the bloodstream, it gets distributed throughout the body by the movement and flow of the blood. Alcohol, chemically speaking, has an affinity for water. The bloodstream will carry the alcohol to all of the various tissues and organs of the human body, and eventually will deposit the alcohol into these areas in proportion to their water contents. Brain tissue, for instance, has very high water content, so the human brain receives a substantial share of the distributed alcohol. Muscle tissue also has a reasonably high content of water; therefore, very little alcohol will eventually be deposited in the body fat of a person drinking alcohol. This is different from drugs like PCP and THC, which are fat-soluble.

Men vs. Women

The natural chemical affinity of alcohol for water, and its lack of affinity for fat, does help explain why alcohol affects men and women differently. The typical female body contains a good deal less water than that of the typical man. This is because women have extra fatty tissue, designed to protect a child during biological development. Scientists have determined that the average male body is about 68 percent water, while the typical female is about 55 percent. Therefore, when a woman drinks, she has less fluid, pound for pound, to receive the distribution of the alcohol.

For example, if a woman and a man who weighted exactly the same drink exactly the same amount of alcohol under similar circumstances, the woman’s BAC could rise faster than the BAC of the man. Add to this the biological fact that the average woman is smaller than the average man; it becomes obvious that an amount of alcohol will cause a higher BAC in a female than in a male.

Body’s Reaction to Alcohol

As soon as alcohol enters into the bloodstream, the human body starts trying to get rid of it. Some of the alcohol will be removed directly from the body in the same chemical state, basically unchanged. Examples of this would be alcohol exiting the body in the form of breath, urine, sweat, tears, etc. However, only a small portion of the ingested alcohol will be eliminated directly. Most of the alcohol ingested is eliminated by metabolic activity. Metabolism is the process of chemical change. In the case of alcohol, it reacts with oxygen in the body and changes, through a series of intermediate steps, into both carbon dioxide and water, both of which get directly expelled by the body.

Most metabolic activity of alcohol in the body takes place in the liver. Enzymes act as catalysts to speed up the reaction of alcohol with oxygen. The speed of the reaction varies somewhat from person to person, and even for any given individual at specific times. On average, a person’s blood alcohol concentration (BAC) will drop by about .015 per hour after peaking. As an example, a person who had a peak BAC level of .015 will take about ten hours to eliminate all of the alcohol.

For the average male, a BAC of .015 is about two-thirds of the alcohol content of the standard drink (a can of beer, a glass of wine, or a shot of alcohol). For the average female, the same BAC would be obtained on just one-half of a standard drink. Essentially, the typical male would eliminate about two-thirds of a drink per hour, while the typical female would only eliminate about half of a drink per hour.

How and What You Drink

People can control the rate in which alcohol enters into the bloodstream; for example, a person could sip rather than gulp down drinks. A person can drink on an empty stomach, or eat before consuming alcohol. Also, the amount of alcohol to be consumed can be changed – a person can drink a lot or a little. However, once alcohol gets into the blood, there isn’t much that can be done to affect the rate in which it leaves the body. A person simply has to wait for the biochemical process of metabolism to move along and rid the body of alcohol.


As a result of people knowing what I do for a living, people often ask me questions such as, “How much can I drink before becoming impaired?” There isn’t a simple answer to these types of questions. I know from experience that any amount of alcohol will affect a person’s ability to operate a motor vehicle. The laws of nearly every state explicitly establish a BAC limit above which it is unlawful to operate a motor vehicle. However, many states also make it unlawful to drive when under the influence of alcohol. So, I often get asked, “How much alcohol does a person have to drink to reach these kinds of BAC levels?” Based on what I have explained so far, it obviously depends. Factors such as the amount of time spent drinking; the person’s gender, size and weight, the contents of the person’s stomach, etc. all matter.

Hypothetically speaking, a 175 pound male who has two beers in a short time period will have a BAC that should be slightly over .04; two more beers will send the BAC over .08. Connecticut’s legal limit for operating a motor vehicle is .08. In this respect, it doesn’t take much alcohol to impair a person legally. A couple of beers at the bar with friends can easily do it.


My name is Teresa, and I am a DUI lawyer, but that is only part of who I am. I have been practicing law in Connecticut since 2006.


My office has operators standing by 24 hours a day 7 days a week. When you need to speak to an attorney, we will be there to answer the call.


Need to get some answers but not able to make a call? Just send us a text and one of my team members will reply ASAP.


Need to reach out via Facebook? Use Facebook Messenger to send us your question.


With offices conveniently located in Stamford, Shelton, New Haven, Waterbury, and New London, we cover the entire state.


sent to you for free