Cocaine is a powerful central nervous system stimulant. Its effects can last from 15–30 minutes to an hour, depending on the method of administration and dosage. Street names for cocaine can reflect its appearance or method of use (such as flake, snow, toot, blow, nose candy, her, she, lady flake, liquid lady, speedball, crack, rock). It can also describe its method of preparation, such as freebase. It is more popularly known simply as coke.

Cocaine increases alertness, feelings of well-being and euphoria, energy and motor activity, feelings of competence and sexuality. Athletic performance may also be enhanced in sports where sustained attention and endurance is required. Anxiety, paranoia and restlessness are also frequent. With excessive dosage, tremors, convulsions and increased body temperature are observed.

Cocaine is currently the most commonly abused major stimulant drug in America, and it has become the drug most frequently involved in emergency room visits. As of 2008, about 15% of Americans used cocaine at some time in their life, 6% by their senior year of high school. As of 2008, 1.9 million Americans had used cocaine in the past month, which includes more than 300,000 people who used crack cocaine.

The trend in drug abuse in the United States is presently multiple or polydrug abuse, and cocaine is no exception. Cocaine is often used with alcohol, sedatives such as diazepam (Valium), lorazepam (Ativan), or heroin, as an upper/downer combination. The other drug is also used to moderate the side effects of the primary addiction.

A common myth is that cocaine is not addictive because it lacks the physical withdrawal symptoms seen in alcohol or heroin addiction. But cocaine does have powerful psychological addictive properties. When cocaine use is stopped or when a binge ends, a crash follows almost immediately. This crash is accompanied by a powerful craving for more cocaine. Additional symptoms may include fatigue, lack of pleasure, anxiety, irritability, sleepiness, and sometimes agitation or extreme suspicion.

In the past, people underestimated the how addictive cocaine can be. However, cocaine is addictive when addiction is defined as a desire for more of the drug, despite negative consequences.