1) "In vino veritas is a well-known Latin phrase. It means “in wine [there is the] truth”. It is also known as a Greek phrase “Ἐν οá¼´νῳ á¼€λήθεια” En oino álétheia, which has the same meaning. The author of the Latin phrase is Pliny the Elder, the Greek phrase is attributed to the Greek poet Alcaeus." "Apparently the phrase refers to the circumstance that people seem to become uninhibited and tell what they really think (i.e. the truth) when they drink alcohol. Already Pliny the Elder, who first mentioned this phrase, called the phrase a saying. The oldest known source for the phrase is the Greek poet Alcaeus. The Roman historian Tacitus tells about the Germanic peoples, that they always drank wine while holding councils, as they thought nobody can deceive effectively when drunken. The phrase is very often continued as "in vino veritas, in aqua sanitas" - "the truth is in wine, the health is in water". A phrase with a similar meaning occurs in the Talmud: בשלושה דברים אדם ניכר: בכוסו, בכיסו, ובכאסו ("people reveal their true personality through drink, money, and anger"). " Source and further information: http://en.wikipedia.org/wiki/In_vino_veritas 2) "Their judgment is not as good—they may express the first thought or action that comes to mind, rather than an appropriate comment for the given situation." "Alcohol has also been linked with lowered inhibitions, though it is unclear to what degree this is chemical versus psychological as studies with placebos can often duplicate the social effects of alcohol at low to moderate doses. Some studies have suggested that intoxicated people have much greater control over their behavior than is generally recognized, though they have a reduced ability to correctly evaluate the consequences of their behavior. Behavioral changes associated with drunkenness are, to some degree, contextual. A scientific study found that people drinking in a social setting significantly and dramatically altered their behavior immediately after the first sip of alcohol, well before the chemical itself could have filtered through to the nervous system. Likewise, people consuming non-alcoholic drinks often exhibit drunk-like behavior on a par with their alcohol-drinking companions even though their own drinks contained no alcohol whatsoever." Source and further information: http://en.wikipedia.org/wiki/Effects_of_alcohol_on_the_body 3) "The motto of the Party had been given by him as: In Vino Veritas, because there was to be speaking, to be sure, and not only conversation; but the speeches were not to be made except in vino, and no truth was to be uttered there excepting that which is in vino--when the wine is a defense of the truth and the truth a defense of the wine." Source and further information: http://www.ccel.org/k/kierkegaard/selections/veritas.htm

It is the truth at the time. Alcohol changes the chemicals in the brain so that feelings and inhibitions are different. What is said is indicative of those changes and are the truth of that moment.