The recognition of acupuncture's effectiveness doesn't depend on the empirical demonstration of its results. There are methodological and conceptual barriers to the establishment of its therapeutical value, on a scientific basis. On the other hand, the increase of demand and supply of alternative therapies implies in a certain legitimation, which depends rather on the recognition of the utility of these practices, than on the demonstration of its scientific status. The crisis of the "scientific medicine" and its mechanistic paradigm may be one of the factors influencing the acceptation of acupuncture in the West. If this is true, scientific studies on acupuncture won't be very useful unless they admit the possibility of a medicine which has its own logic, different from the western science. Perhaps the greatest contribution brought by the East to the western medicine is its knowledge, and not its technique. But it's only through the understanding of the chinese culture and civilization, the acceptance that Yin and Yang form a coherent system, that the tradicional knowledge can be really seized.