The benefits and risks associated with moderate drinking have gained increasing attention in recent years from both researchers and the public, but there is no universal definition of moderate drinking. Most current definitions are based on a certain number of drinks consumed in a specific time period. However, it is difficult to define a drink, because alcoholic beverages can differ substantially in their alcohol content, even within the same beverage category (e.g., beer, wine, or distilled spirits). International differences also exist in drink definitions; therefore, comparing studies from different countries is difficult. Variations in the survey methods and assessment modes used to assess alcohol consumption levels and drinking patterns further hamper the development of a universal definition of moderate drinking. Despite these problems, definitions of moderate drinking and drinking guidelines have been developed in the United States and other countries. The Dietary Guidelines developed by the Department of Health and Human Services and the United States Department of Agriculture define moderation as no more than one drink per day for women and no more than two drinks per day for men. A drink is considered to be 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of 80-proof distilled spirits. The guidelines also list several categories of people who should not drink at all. The development of methods for accurately determining peoples alcohol consumption and drinking patterns will greatly enhance researchers' ability to define moderate drinking and clarify the associated benefits and risks. 18 references (Author abstract modified)