The following explains the basics of alcohol and the human body. The most commonly used intoxicating substance in society today is alcohol. Alcohol consists of an organic compound, defined as a compound comprised of naturally occurring elements with carbon atoms. The most common members of the alcohol family include ethanol and methanol. The alcohol in a beverage is ethyl alcohol or ethanol, which molecularly is H3C2-OH. The OH group at the end of the group of molecules is what makes the compound an alcohol.

Alcohol Ingestion

When alcohol goes into the body, it passes from the stomach into the small intestine. There, it gets absorbed by the blood and transposed throughout the body. Because of the quick pace that alcohol moves throughout the entire body, it can reach and affect the central nervous system even in small concentrations. The more alcohol ingested, the more it will impact the central nervous system. Also, it will act as a central nervous system depressant. The functioning of the central nervous system gets affected by the amount of alcohol consumed.


Alcohol impairs each of the functioning systems of the body differently. Alcohol consumption can cause the central nervous system to:

  • Impair motor skills.
  • Decrease inhibitions.
  • Impair judgment and body control.
  • Induce mental confusion, vomiting, tiredness and respiratory arrest, which could result in death.

For the most part, people in the United States know their limit and control their alcohol intake without problems.


Alcohol enters the body through absorption. This is the first stage of a three stage process of absorption, distribution and elimination. The three processes happen simultaneously, with absorption happening first. This happens first because it is necessary to introduce the alcohol into the body.

Absorption of alcohol is the process by which alcohol is transferred from outside the body to the stomach, small intestine and then throughout the body through the bloodstream. Once ingested, alcohol gets constantly absorbed into, and eliminated from the body. The rate of absorption is variable. It is affected by:

  • The presence of food in the stomach.
  • Food composition (carbohydrates or fats).
  • The alcohol concentration of the beverage consumed.
  • The rate of consumption.
  • Uptake from the stomach and duodenum.
  • Your emotional state.
  • The time of day.

Ingested alcohol not yet absorbed from the stomach and intestines has no neurological effects. Also, it cannot cause driving impairment. Conversely, alcohol fully absorbed may cause driving impairment, if at a level which impairs driving. Consequently the time frame in which alcohol gets absorbed into the bloodstream and the corresponding volume absorbed are matters of great significance in predicting an ultimate blood alcohol concentration.

Impact Factors

Any medications that you are taking can increase the effects of alcohol, so be sure to check the labels on the medications or consult a physician before drinking and taking medication. Some medications will react violently when combined with alcohol and antibiotics may become ineffective when taken in combination with alcohol. In some cases, people face DUI charges as a result of mixing medication with alcohol. The medication alone might not have impaired driving abilities, and perhaps there person only consumed a small amount of alcohol, but combined the effects can act on the body in stronger ways.

The different types of alcohol that a person ingests can affect the consumption rate due to the difference in the actual concentrations of alcohol in different alcoholic beverages. If a drink has an alcohol concentration between 10% and 30% such as beers, malt liquor and many table wines, they are absorbed more quickly than those above 30% and below 10%. This often plays a role in the increasing blood alcohol level after a person ingests a shot prior to leaving the social event. The shot will absorb much slower than the beer they may have been drinking, and may increase a person’s blood alcohol level while the person is in police custody. In these cases, your BAC at the station might be at or above .08, but while you were driving, it might have been much lower. As a result, the BAC test results can be misleading.

Body Type

Those drinks with lower alcohol content tend to be missed by the body while in the gastrointestinal tract and they absorb very slow and large quantities can delay the process of gastric emptying. Amounts higher irritate the mucous membranes causing increased secretion of the mucous and again slowing the process of gastric emptying. Therefore, two people with similar body types can drink the same amount of alcohol but if the individuals are of different weights then one will have a larger percentage of water in the body and therefore will become intoxicated less quickly. An individual with more muscle mass will most likely be less affected than someone with a higher body fat content due to the fact that fatty tissue does not contain very much water and will therefore not absorb much of the alcohol.

Blood Alcohol Content

At any particular blood alcohol content, a driver may be significantly less impaired than another due to a greater tolerance to the effects of alcohol. For this reason, a driver’s apparent sobriety as seen through an obvious lack of impairment or a demonstration that the driver could perform tasks in a sober manner, sometimes may be used as evidence to rebut an incriminating blood alcohol test result.