Background: Informed consent is regarded as a contract between autonomous and equal parties and requires the elements of information disclosure, understanding, voluntariness and consent. The validity of informed consent for critically ill patients has been questioned. Little is known about how these patients experience the process of consent.Objective: The aim of this study was to explore critically ill patients’ experience with the principle of informed consent in a clinical trial and their ability to give valid informed consent.Design: 11 stroke patients (...) who had been informed about thrombolytic treatment and had been through the process of deciding whether or not to participate in a thrombolysis trial went through repeated qualitative semistructured interviews.Results: None of the patients had any clear understanding of the purpose of the trial. Neither did they understand the principles of randomisation and voluntariness. Reasons for giving or not giving consent were trust, conceptions of benefits and risks and altruism. Several patients found it immoral to involve patients in the consent procedure and argued that this was the doctors’ responsibility. Others argued that it is a duty to question patients and perceived it as a sign of being treated with respect and dignity. A majority of the patients found the consent process vague and ambiguous.Conclusions: The results indicate that the principle of informed consent from critically ill patients cannot be seen as a contract between equal and autonomous parties. Further studies are needed to explore critically ill patients’ experiences with the process of informed consent. (shrink)