Alcohol:

An alcoholic beverage is a drink containing ethanol (commonly known as alcohol, although in chemistry the definition of alcohol includes many other compounds). Alcoholic beverages are divided into three general classes: beers, wines, and spirits.
Most nations regulate the production, sale, and consumption of alcoholic beverages. In particular, laws often specify the minimum age at which a person may legally buy them, or even drink them. This minimum age varies from 16 years in Germany, the Netherlands, France, Austria, and Switzerland to 21 years in the United States. In Germany, 14-year-old persons may buy low-alcohol beverages, if their parents are present. Alcoholic beverages are part of most European cultures; children in these cultures may occasionally drink alcohol during meals with their family.
When large amounts of alcohol are consumed in a short period of time, alcohol poisoning can result. Alcohol poisoning is exactly what it sounds like — the body has become poisoned by large amounts of alcohol. Violent vomiting is usually the first symptom of alcohol poisoning. Extreme sleepiness, unconsciousness, difficulty breathing, dangerously low blood sugar, seizures, and even death may result.
Teens who drink are more likely to be sexually active and to have unsafe, unprotected sex. Resulting pregnancies and sexually transmitted diseases can change — or even end — lives. The risk of injuring yourself, maybe even fatally, is higher when you're under the influence, too. One half of all drowning deaths among teen guys are related to alcohol use. Use of alcohol greatly increases the chance that a teen will be involved in a car crash, homicide, or suicide.