Recent use of psychoactive substances among 456 medical students throughout the six grades was surveyed by way of a self-report questionnaire using World Health Organisation criteria. Among male medical students, the most frequently used substances were alcohol (80.5%), cannabis (25.3%), solvents (25.2%), and tobacco (25.2%), whereas among female students the most frequently used drugs were alcohol (72.6%), tobacco (14.6%), solvents (10.5%), and tranquillizers (7.5%). Switch from illegal to legal drugs were observed only among female medical students. Male students tend to alternate cannabis and solvents throughout college years. Interventions aiming to influence patterns of drug consumption among medical students must consider both gender differences and evolutional patterns of substance use throughout medical course.