Background Ethics consultations are established in contemporary health care. Informal ethics consultations often occur and are possibly beneficial, yet they have not been empirically studied. We sought to describe features of informal ethics consultations and to identify facilitators and disruptors of patient participation in such ethics consultations. Methods We used a mixed methods (quantitative and qualitative) evaluation design and conveniently sampled 64 sequential informal ethics consultations over a period of 3 years in two academic health care centers in one city (...) in Canada. Data were collected by the two participating ethicists. We used statistical description for the quantitative data and thematic analysis for the qualitative data. Results Patients participated in only two (3%) of the informal ethics consultations. Factors that disrupted patient participation in ethics consultations were related to patients’ issues (mental impairments), family issues (family withholding information from the patient), and team members’ issues (efficiency considerations). Conclusion Informal ethics consultations may be used for ethics capacity building of health care providers rather than for engagement with addressed patients. Further research on informal ethics consultations is required, including in different sites. (shrink)