Background:Drugs may be used medically to modify or control mood or state ofmind. Examples include taking an antianxiety agent for an acute anxietystate in accordance with a physician's prescription. The use of a substanceto modify or control mood or state of mind in a manner that is illegal orleads to adverse effects on the individual's physical and mental health isconsidered abuse. Substance abuse is the overindulgence in anddependence of a drug or other chemical It is considered a disorder and ischaracterized by a pattern of continued pathological use of a medication,non-medically indicated drug or toxin, that results in repeated adversesocial consequences related to drug use, such as failure to meet work,family, or school obligations, interpersonal conflicts, or legal problems.Substance abuse poses a serious threat to the health of children andadolescents. In addition to the health risks inherent with alcohol and otherdrug use, substance abuse often is linked with other risk behaviors (earlysexual activity, violence, academic failure, school dropout, anddelinquency).• Objective:This essay will focus on substance abuse and addiction in terms of;the most important substances abused, medicolegal importance andprevention in pediatric age group. Conclusions:Paediatricians and other primary care providers are in an ideal positionto identify substance abuse and to provide preventive guidance andeducation to children, adolescents, and their families. There is a strongpositive relationship between substance abuse and violent crime.Substance abuse has become an exceedingly important issue withinthe correctional component of the juvenile criminal justice system.The observed high correlation between crime, substance abuse andpoor mental health suggests that factors which reduce substance abuseand improve mental health may also be effective in reducing criminalactivities