Rubbing alcohol is made mostly from isopropyl alcohol and a little water. Other alcohols, such as methanol, are often mixed with it at very high concentrations to produce a distinct smell and deter its consumption. It is denatured, which means that it has been made poisonous. The concentrations and types of alcohol used are very toxic to humans and can quickly cause brain damage or death.
Alcohol that is relatively safe for human consumption is ethanol based and contains much less alcohol produced by distillation or the fermentation of sugars. This keeps the amount of alcohol in a drink much lower than the concentration found in rubbing alcohol. Rubbing alcohol is close to 100% alcohol.
Both kinds of alcohol are toxic to the human body, however. Because of the much lower concentrations found in beverages, the affects are rarely life threatening. Alcohol should be consumed in moderation to prevent alcohol poisoning, which can be fatal.
The mixture of alcohols found in rubbing alcohol is what produces its odor. This can be used to identify the liquid, acting as a warning to those handling it that it is not consumable. Methanol is very poisonous to humans, even in small concentrations.
Ethanol found in beer is produced as a byproduct of the reaction between sugars found in the yeast and malt used in the brewing process. When the yeast is added, it feeds off of the sugar, producing carbon dioxide and alcohol. Once the alcohol gets to a certain level, there will not be enough sugar left to continue feeding the yeast, which can then be filtered out of the mixture. This keeps the amount of alcohol between 4 and 12% by volume.
The distillation process also produces ethanol in other beverages. The concentration in these drinks is usually higher than that produced during the brewing process, depending on the methods used, but does not come close to the amount of alcohol found in rubbing alcohols.
The effects of rubbing alcohol are similar to those of ethanol in that they can cause the same symptoms, but its absorption rate is much faster and the effects are seen far sooner. While someone who swallows a small amount is not likely to die, it is possible, depending on the amount consumed. If someone accidentally ingests isopropyl alcohol, he or she should seek medical attention or contact the poison control center immediately.