The formalization of the obtaining of the consent of the patients who take part in a study through the Sheet of consent is appraised positively, without harm which it would be necessary to point out that the cession of the "data clinical and of the treatment" in the Center of studies, he will, only, limit to those that are relevant to the effects of the study (article 4 LOPD); that the patient is recommended to identify the responsible hospital that requests the consent to; that it would be convenient to pick up the DNI of the patient or the CIP, etc, in order to avoid confusions among several persons with the same ones name and surnames; and that it would be necessary to inform about the possibility to revoke the consent and about the possibility to exercise the rights I ARCO in relation to the data treated in files of the Center of studies.