What is a single occasion of drinking?

A single occasion of drinking is any time a person consumes one or more drinks containing alcohol and during this period of time their blood alcohol concentration (BAC) does not return to zero.

A single occasion of drinking might include drinking at home followed by drinking at other venues. For example, someone may drink two beers at home, then a glass of wine at a restaurant, followed by a shot of spirits at a pub. If this person's BAC did not reach zero at any time between these drinks, this constitutes a single occasion of drinking.

Source: National Health and Medical Research Council (NHMRC) (2009). Australian guidelines to reduce health risks from drinking alcohol.

Blood Alcohol Concentration (BAC): A commonly used measure of alcohol intoxication. It refers to the amount of alcohol present in the bloodstream. For example, a BAC of 0.05% means that there are 0.05 grams of alcohol in every 100 millilitres of blood.

Single Occasion of Drinking: Any time a person consumes one or more drinks containing alcohol, and during this period of time their blood alcohol concentration (BAC) does not return to zero.