With Evidence-Based Medicine, shared decision making is attracting considerable interest as a means by which patient preferences can be incorporated into clinical decisions. Patients cannot express informed preferences unless they are given sufficient and appropriate information, including a detailed explanation concerning their condition, the different therapeutic options and the likely outcomes with and without treatment. A patient education leaflet is a potentially powerful tool for communicating information to patients, who will be able to participate in the process of decision making. The present article is a review of available guides for the writing of patient information materials. It also includes criteria for evaluating their quality.