Background and Purpose - To involve stroke patients and carers in the design of a study of oxygen supplementation in acute stroke and to obtain their views on the importance of the study, consent issues, relevance, and acceptability of the outcome measures, and the preferred method of follow-up. Methods - This study involved qualitative and quantitative research. Three focus group meetings were held with individuals who have had personal experience of stoke, mostly stoke patients and their partners or carers (an association of young stroke sufferers and 2 dysphasia support groups each from a different town in the West Midlands, UK). The researchers explained the planned oxygen supplementation study and encouraged participants to comment and make suggestions in a semistructured interview. The audience was then asked to complete a questionnaire relating to the study. Results - Seventy-three people (67% stroke patients and 33% carers; mean age 64; range 31 to 86 years; and 47% males) attended the 3 meetings. The overall response rate to the questionnaires was 70%. Most of the respondents considered the study worthwhile (97%) and the planned outcome measures relevant. In addition, assessment of speech, memory, sleep, and cognitive function was raised by > 20% of respondents as important outcomes. Seventy-five percent would agree with assent from a family member on behalf of incompetent patients, and 92% would agree to a doctor recruiting incompetent patients to the study and seeking consent/assent later. The majority of respondents (80%) preferred personal contact with the researcher or a representative to a questionnaire for follow-up. Conclusions - Involvement of stroke patients and carers helped us identify outcome measures that are important to the stroke population but not routinely addressed in stroke assessment scales. A high proportion of respondents asked for waiver of consent and agreed to family's assent on behalf of incompetent patients. Although consumer involvement has helped us to make the study more relevant to the public, it has also led to difficult scientific and ethical conflicts in protocol design.