One of my earlier posts, "Immaculate Intoxication", created considerable interest on the internet. Few of us realize that alcohol is actually produced within our bodies, independent of any drinking — a relatively common phenomenon scientists refer to as the "autobrewery syndrome". A common cause is fermentation created by the presence of yeast and glucose in the system.
Internally-produced alcohol can be caused by other things as well. If an individual was taking antacids such as Tums or Rolaids, for example, he may have created a situation in which his body was manufacturing alcohol internally. Scientific literature indicates that antacids change the gastric acidity in the stomach — which can lead to alcohol production by resident bacteria…. and elevated blood-alcohol readings in a DUI investigation. See "Effects of Cimetidine Treatments on Ethanol Formation in the Human Stomach", 19(6) Scandinavian Journal of Gastroenterology 853 (1984); and "Effects of Antacids on Alcohol’s Reaction", 5(5) Alcoholism 28 (1985).