University of Sussex experts studied government advice in 57 nations, including EU states.
They said the lack of agreement was 'remarkable' about what constitutes harmful or excessive drinking on a daily or weekly basis and even when it is safe to drive.
The Scottish Government faces a legal challenge over its plans for a minimum unit price of 50p on alcohol from the Scotch whisky industry, which claims the legislation breaches EU trade rules.
Justice Secretary Kenny MacAskill also wants more powers to be devolved from Westminster, to allow the threshold for drink driving to be cut from 80mg of alcohol per 100ml of blood down to 50mg,
Sussex University's Dr Richard de Visser said: "We were surprised at the wide variation in guidelines. There is no international agreement about whether women should drink as much as men or only half as much."
Calls have now been made for internationally-agreed standard definitions of alcohol units and consumption guideline.
The research found some countries referred to standard drinks but failed to define them in grams of ethanol. Eight of the 27 EU member states did not have readily accessible guidelines.
The study is published in Drug and Alcohol Review.