Although users sometimes resort to practices that do not comply with biomedical recommendations, they do so in order to attain the values and exigencies of biomedicine as regards the validation or personalisation of treatments. However irrational and peculiar these practices may appear, the mechanisms on which they are based do not necessarily break away from medical recommendations. Therefore, anthropologically speaking, we cannot oppose good and bad practices in terms of medicinal uses, since what health professionals would consider to be bad practices are thought by patients to be in keeping with good use.