In this discussion of alcohol, it is clear that we have been referring to "booze," "suds," "the sauce," "hooch," or any of the other colloquial terms for beverage alcohol. To be scientifically accurate, "our kind" of alcohol is called ethanol, ethyl alcohol, or grain alcohol. Alcohol, if one is precise, is a term used to refer to a family of substances. What all alcohols have in common is that each has a particular grouping of carbon, hydrogen, and oxygen atoms, arranged in a similar fashion. They differ only in the number of carbons, and their associated hydrogens. Each alcohol is named according to the number of carbons aboard. Ethanol has two carbon atoms.
The other kinds of alcohol with which everyone is familiar are wood alcohol (methyl alcohol) with one carbon, and rubbing alcohol (isopropyl) with three carbons. With their different chemical makeup, they cause big problems if taken into the body. The difficulty lies in differences in rates of metabolism and the kinds of byproducts formed. For example, it takes nine times longer for methanol to be eliminated than ethanol. Although methanol itself is not especially toxic, when ADH acts on it, formaldehyde instead of acetaldehyde is formed. Formaldehyde is known to cause tissue damage, especially to the eyes. The formaldehyde then breaks down into formic acid, which is also not as innocent as the acetic acid produced by ethanol metabolism, and can cause severe states of acidosis. Ingestion of methyl alcohol can lead to blindness and can be fatal; thus it requires prompt medical attention.
As an interesting aside, the treatment of acute methanol poisoning is one of the handful of situations in clinical medicine where ethanol has a legitimate and important therapeutic role. In this situation giving ethanol will slow the rate of metabolism of methanol and reduce the level of toxic byproducts. This happens because the ethanol successfully competes with methanol for ADH. This effect, in conjunction with correction of acidosis, may ameliorate or entirely eliminate serious complications, if ethyl alcohol is administered rapidly enough.
Poisonings from nonbeverage alcohols don't just happen to alcoholics who in desperation will drink anything. Recently, there have been reports of an Italian wine scandal; table wines were laced with methanol resulting in upwards of 100 deaths. Far more common is the toddler who gets into the medicine cabinet, or maybe the teenager or adult who doesn't know that all alcohols are not the same and have different effects.
At present, it is becoming common knowledge that anything taken into the body (or breathed in for that matter) has effects on the body. All too often we are discovering these effects to be more harmful than had been previously thought. Chemical additives, fertilizers, and coloring agents are being found to be less benign than once supposed. Caution is urged in the use of all such agents, and the federal Food and Drug Administration (FDA) has outlawed some of them. Let us hope that this caution will begin to extend to the use of alcohol as well.