The dangers of drugs among teenagers are most vulnerable to damaging the younger generation, especially students, this has an impact on the learning process of students at school and various aspects of computer development. Students who have done drugs can be provided through basic services such as prevention related to the dangers of drugs. This study aims to analyze students' understanding of the dangers of drugs through information services. The approach used in this research is experimental quantitative in the form of one group pretest-posttest. The research was conducted at the State Junior High School 2 Trumon Timur, the objects in the study were 40 students in grades VII-VIII, determined by recommendations from the BK teacher at the school where the study was conducted. This study uses T-test analysis. The results showed that after the treatment, students experienced an increase in understanding from a low level of understanding to a high level of understanding after information services. Thus there is a clear difference between before and before treatment is given.