This article is an integrative literature review whose aims were to analyze the understanding and readability of informed consent forms applied to participants of researches involving humans, and to check the factors that influence their understanding and readability. Therefore, it intended to identify factors associated with the problem of obtaining a valid consent. The sample included eleven articles selected for this review, national and international, four of which were in Portuguese (36,36%), one in Spanish (9,10%) and six in English (54,54%). It was concluded that most of the studies analyzed confirms the hypothesis that the participants do not understand what they read in the informed consent form. Thus, the factors inferred as responsible for the difficulty in reading and understanding the informed consent forms were the educational level of the participants and the language used in the terms.
Informed consent; Reading-Comprehension