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Elimination

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  p369-370

2026-08-12

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Elimination

There are two routes to the elimination of alcohol by the body. Metabolism accounts for more than 90% of elimination. It takes place mainly in the liver, which has an enzyme, alcohol dehydrogenase that first converts ethyl alcohol to acetaldehyde and then to acetic acid. The acetic acid is used by cells for energy and forms carbon dioxide and water. Metabolism takes place at somewhat different rates in differ ent people. The average rate is about 0.015 ± 0.003%/h. This rate of elimination is approximately equivalent to less than one drink containing one ounce of 100 proof (50%) alcohol per hour. If an average man takes in enough alcohol to reach a maximum BAC of 0.23%, it would take more than 10 h to reduce the level below 0.08%, which is the legal limit in some states to be charged with operating under the influence of alcohol (OUIL).

The remaining few percent of alcohol is eliminated from the body as ethyl alcohol by excretion. This includes urine, breath, and perspiration. From this information, it can be easily seen that exertion, showering in cold water and other activities will have little or no effect on BAC. Removal of alcohol from the body is largely under the control of the liver, which doesn’t react to contrition, anger, or pleading! It should also be noted that ingesting large amounts of caffeine in coffee, for instance, would not help much. Caffeine is a CNS stimulant and alcohol is a depressant, but they work on different brain receptors and do not cancel each other out. Taking caffeine while being drunk will leave you wide awake… and drunk! Some people believe that vigorous exercise will eliminate alcohol more rapidly. Since only a small percent of alcohol is removed through exhaling and/or perspiration, this will have little effect on the BAC. It should be obvious that taking a cold shower will also not affect the concentration of alcohol in the bloodstream.