Compliance to treatment is of crucial importance in medicine. High levels of noncompliance to treatment have been reported in the most relevant diseases such as hypertension, coronary artery disease, diabetes and asthma. The aim of this article was to fully evaluate the lack of adherence to treatments in internal medicine. The prevalence of noncompliance and methods to cope with it are presented. The theory of the stages of change is thoroughly examined. Motivational interviewing in low-compliant patients is illustrated dealing both with the theoretical principles and practical applications. Several communication blocks which interfere with the relationship between doctor and patient are finally presented through concrete examples.