Abstract In healthcare settings, patient participation is increasingly adopted as a possible remedy to ill people suffering from ‘epistemic injustices’ – that is to their unfair harming as knowers. In exploring and interpreting patient participation discourses within the 2013–2018 Dutch Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS) Health Council advisory process, this paper assesses the epistemological emancipatory value of this participatory practice. It reveals that in the analysed case, patient representatives predominantly offer biomedical knowledge about ME/CFS. They frame this condition as primarily somatic, and accordingly, perceive appropriate diagnostic criteria, research avenues and treatment options as quantifiable, objectifiable and explicitly non‐psychogenic. This paper argues that such a dominant biomedical patient participatory practice is ambiguous in terms of its ability to correct epistemic injustices towards ill people. Biomedicalized patient participation may enhance people's credibility and their ability to make sense of their illness, but it may also undermine their valid position within participatory practices as well as lead to (sustaining) biased and reductive ideas about who ill people are and what kind of knowledge they hold. The final section of this paper offers a brief reflection on how to navigate such biomedicalized participatory practices in order to attain more emancipatory ones.