The triple therapy have been used since 1996 to treat patient with HIV. The OST have been used since 1995 to treat drug addicts. All these treatments have in common to have deeply modified the relationship between patient and their illness, and to often give troubles behaviour with living with treatment. The nursing staff supports these patients by using specific professional practices. Theoric models can be used to decode the nursing practice. Two studies of these support practices with two different publics (patients with HIV and substituted drug addicts) shows us the most used health model--a biomedical vision in which health means no illness--And therapeutic education in an instruction way, in order to teach the scientific knowledge to patient to educate. The professionals have an agent posture for an injunctive and prescriptive medical practice. But in the same supports, other ways are used by professionals: they are based on individual development and its adaptation. Becoming aware of the elements of the therapeutic education relationship can modify the interaction between nursing staff and patients. Professionals could move from an agent posture to a reflexive process allowing to patients will become more autonomous in their health attitudes.