Research indicates there is confusion in the minds of patients and the public surrounding the issue of 'informed consent'. This confusion is compounded when patients are asked to participate in a clinical trial. This study aimed to survey, by self-completed postal questionnaires, the experiences and opinions of 100 randomly selected healthy volunteers not in a clinical trial, 100 healthy volunteers in a clinical trial and 100 breast cancer patients in a clinical trial. A 71% response rate was achieved. The results indicate that there are areas in the current procedure which scored highly and some where improvements could be made. Overall, 72% of respondents indicated they were satisfied with the level of support they are currently receiving. The results also show that healthy volunteers in a clinical trial were better informed about the trial than the corresponding cancer patients. They were given more written information (86% versus 60%, P < 0.005), had a better indication of their time commitment (81% versus 62%, P < 0.025), were better informed of possible physical discomforts (61% versus 43%, P < 0.05), were better informed of possible side-effects (75% versus 57%, P < 0.025) and were more aware of their rights to withdraw from the trial (84% versus 46%, P < 0.005). Patients were also asked for their opinions on their requirements for giving informed consent. The overwhelming majority of the women responding to Questionnaire 2 wanted all the information and support outlined. Only two areas scored below 90%: those were concerned with wanting assurance that all information about the patient will be kept confidential (75%) and those wanting information on protection of the patient's privacy (66%). This response appears to be against the general trend. These results clearly show that most patients require access to a wide range of information prior to consenting to treatment or inclusion in a clinical trial.