If you have ever wondered what causes hangovers the answer to that question is simply this, hangovers are caused by drinking more alcohol than your body can handle. Even a single alcoholic drink can trigger a hangover for some people. Some other others may drink heavily and escape a hangover entirely. Generally, however, more than three to five alcoholic drinks for a woman and over five to six for a man will usually result in a hangover. About 75 percent of people who drink alcohol to intoxication will have a hangover the next day.