Aversion therapy is a form of behavior therapy that uses negative reinforcement to reduce undesirable behaviors. It works by pairing an aversive stimulus, like an electric shock, nausea-inducing medication, or unpleasant smell/taste, with the undesirable behavior. The goal is to condition the individual to associate the behavior with the unpleasant stimulus so they learn to avoid the behavior. Common applications include treating alcoholism, nail-biting, or other addictions/habits by using stimuli like electric shocks, Antabuse medication, or foul smells.