The Quarter of the psychiatric disorders start below the age of 24. The substance used by the medical students are alcohol (24%), cannabis (11.8%) and tobacco (17.2%), in additon 9.9% use is of hypnotic and sedative. Cocaine use is about 2.1% and stimulants are being used by them 7.7%. very low percentage of opiate is also been ued which is 0.4% specially in latin america. Mostly substance use is found in final year students. A cross-sectional descriptive was conducted among the undergraduate Medical students of ty larkana. Data was collected using online questionnaire and the results were analyzed by SPSS 23 with the help of mean and percentages. Majority of students ranged from age group of 22-23 (32.8%). 41.1% Studnets living with more than 5 family members, 79.7%, participants did not use drugs ever, 72.4%, never tried ciggerates, 86.5% have never tried marijuana cannabis,73.7% are never on drugs, 92.9% never used amphetamine crystals, 62.5% participants were aware regarding drug related information, its prevention, treatment and side effects. 70.3% participants never have any withdrawal symptoms which may be due to being non user, 52% of the participants were unaware about the potential risk and dangerous association with cocaine use. 54.9% of the participants were unaware not familiar with the available resources and support services regarding quitting tobacco.67.9% of the participants were unaware of the potential risk and dangerous effects associated with cocaine. Policies must be formed to avoid usage of these substances and and strictess must be observed on the students.