Sedation is helpful for dentist in treating children with uncontrolled behavior. Ideal sedation is to maintain close to normal consciousness and establish a non-negative physiological response. Four types of sedation were used in pediatric dentistry including nitrous oxide oxygen, sedative-hypnotics, phenothiazine, and narcotics. It is important to provide enough sufficient oxygen and monitor vital signs while in effective sedation. The purpose of this article is to discuss the effectiveness of these sedative drugs and their side effects.