Drugs have been used since the earliest civilisations. They were initially used mainly in religious rituals. Since the 20th century, with the emergence of new drugs, especially synthetic ones, these substances have become a problem for society as a whole. Although this social problem affects the entire population, the school environment is a place where the effects can be even more damaging, as they affect a very important part of the population, adolescents. With this in mind, the aim of this study is to find out about the knowledge of seventh-form students at Divina Providência school about drugs, what means they use to acquire information about these substances, and whether these students have ever used any psychoactive substances.