https://www.selleckchem.com/products/pi4kiiibeta-in-10.html INTRODUCTION The consumption of substances is a common practice among the medical students and their use might reduce educational and clinical performances as well as judgment of the students. This study aims to find out the prevalence of substance use among medical students in BP Koirala Institute of Health Sciences. METHODS A descriptive cross-sectional study was carried out among medical students of BP Koirala Institute of Health Sciences from 15th September 15th to December 15th 2018 after obtaining ethical approval from the Institutional Review Committee (Ref 1394/017). The study was conducted among 326 medical and dental students from first to fifth year by using the stratified sampling method. A self-reported questionnaire was developed which included types, frequency, duration, age to first use, and motives for the use of different substances. Data was analyzed using Statistical Package for Social Sciences version 11.5. RESULTS The prevalence of substance use among medical students of BP Koirala Institute of Health Sciences was 196 (61.4%) at 95% Confidence Interval (56.05-66.75%). Among substance use, the use of alcohol 190 (59.6%), tobacco 90 (28.2%), and marijuana 38 (11.9%) was more prevalent. One hundred forty four (45.2%) male students used more substances as compared to 52 (16.3%) female students. Fun sake or partying 131 (68.9%) was the main motivation of the students to use substances. CONCLUSIONS The overall substance use among medical students was high compared to other studies. Alcohol was the most common substance misused by the student followed by tobacco and marijuana. Proper counseling and awareness programs about the potential risk of substances are recommended for the betterment of the students.INTRODUCTION Endoscopic sinus surgery is a well-known approach for sino-nasal pathologies. Due to close proximity to the brain and orbit, the surgeon should be aware of the sino-nasal anatom