[Knowledge and willingness to participate in research: a descriptive study of volunteers in a clinical trial].

The aim of this study was to evaluate volunteers' knowledge of the information on the free informed consent form and their willingness to participate in a clinical trial. This was a quantitative, descriptive, cross-sectional study conducted in November 2011 with subjects from a clinical trial in Americaninhas, northeast Minas Gerais State, Brazil. A convenience sample included 143 adults of both sexes, 18 to 45 years of age. A structured questionnaire was applied one week after signing the free informed consent form. Most participants signed the free informed consent without sufficient knowledge of the research information and were influenced in their decision to participate in the trial. The authors conclude that signing the free informed consent form fails to express all participants' autonomy in clinical trials.