The purpose of this research was to study behavior of Isotretinoin usage in adolescent and related medical problems. The study used questionnaires on 206 samples, adolescents age 13-19 years old. The research revealed that most adolescent used antiacne when they suffered from acne(63.6%). They started using Isotretinoin when the involved skin got mild inflammation or pus collection (51.5%) and Isotretinoin taken was from beauty clinics (34.0%), friends (18.4%),internets (18.4%). The significant reasons of adolescent decision to use the drug are doctor's recommendation, friends' recommendation and good result of antiacne, accordingly. However most adolescent didn't aware to begin the necessary of pre and post health checking up (98.5%).Most adolescent had already known about drug side effects and some of them got side effect. The most common side effects are dry mouth, dry skin, dry eyes and dry nose (93.2%). Moreover, the influent factors of making decision for using Isotretinoin are efficiency, side effect, trend of acne care from the internet’s advertisement and friends' recommendation, accordingly.