According to Francesca Guarino, Cannabis social use and diffusion are dependent on the methodological way of observing. In the first part of the article, the author exposes a profile of consumption taken from the statistical sources. By which, she tries to demonstrate how this kind of data leads to a medical and normative point of view. In the second part, phenomenological and qualitative studies are considered as a more consistent and deeper approach in their description of the meanings and the attitudes of joint-smokers. In particular, these studies focus their attention on patterns of use, reasons, perceived effects and styles of normal cannabis consumption. The author proposes that qualitative methods should be more considered in order to understand the increasing number of person who use cannabis as a rational choice.