L'articolo evidenzia e discute alcune particolarità del mercato sanitario (in particolare l'asimmetria informativa tra domanda e offerta nonché, il ruolo dei media nel promuovere presso la società civile una visione mitica di efficacia dell'impresa medico-sanitaria) che impediscono al cittadino-paziente di esprimere preferenze di consumo tecnicamente fondate. È inoltre descritta la dinamica attualmente in atto che tende, tramite [i] l'abbassamento delle soglie che definiscono "il patologico" [ii] la diffusione degli "screenings" e [iii] la creazione di nuove "patologie", a trasformare cerchie sempre più vaste di popolazione da soggetti "soggettivamente sani" in individui "oggettivamente ammalati". Stante questa situazione sono discusse le modalità ed i risultati della partecipazione dei cittadini alle decisioni medico-sanitarie che li concernono. Infine è proposta un'azione culturale verso la società civile che miri a ricondurre le attese verso l'efficacia dell'attivismo medico-sanitario alla realtà dell'evidenza. [Autore] Some key issues of the health care market (as information asymmetry between supply and demand, difficulty to reach an informed consent, the societal mithical view of effectiveness of every medical service proposed by the market) are discussed in the aim to point out the difficulties to allow the consumer-patient to express "evidence-based" preferences. Without an adequate level of relevant information the consumer tends to accept every service proposed by health care market not only in the hope to maximise health benefits but also to minimise "regret". It is also pointed out that the main threats to an informed patient choice are represented by the lay press and by the "educational" materials produced by professionals. In fact media have plunged the civil society in an overly optimistic and "mythical" view of the effectiveness of medicine in general by spreading to the community messages that (i) emphasise benefits of medical services (even if only potential), (ii) gloss over uncertainties, adverse events and side effects and (iii) ignore legitimate scientific controversies.The same is true for most leaflets and materials developed by professionals and agencies to inform and educate pazients. This "magnification of the power of modern medicine", perceivable in almost every mediatic health input to the civil society, not only suits the interests of the health care providers, but also those of the public itself, which undoubtedly prefers to receive reassuring and benefit-emphasising messages, rather than more complex ones likely to induce anxiety and distress. This results in a growing gap between expectations and reality, in an increasing demand of health goods for a potentially unlimited well-being and in a deeply established perception by the public that all prescriptions are necessary, effective and adequate. Not surprisingly between 70% to 80% of the general population believe that medicine has to be considered as an "exact (or almost exact) science". [Author]