Like many medications, how Campral works is not completely understood. However, alcohol is believed to have wide-ranging effects on the chemicals in the brain. Excessive long-term use of alcohol can actually disrupt the balance of the brain's chemistry. It is believed that this change is linked to alcohol dependence.

When a person stops drinking, his or her brain reacts to the absence of alcohol by sending out signals of stress and agitation. Even after the initial withdrawal period, the brain may continue to send signals that cause distress (e.g. anxiety, sweating, difficulty sleeping).

People usually start drinking again to relieve these symptoms of distress.

Campral is believed to help restore the chemical balance and prevent the feelings of discomfort associated with not drinking. Many people taking Campral report they spend much less time thinking about drinking. Campral, in combination with counseling or support groups, makes it easier for people not to drink.