In medical research, the ethical principle of respect for persons is operationalized into the process of informed consent. The consent tools should be contextualized and adapted to the different socio-cultural environment, especially when research crosses the traditional boundaries and reaches poor communities. We look at the challenges experienced in the malaria Quinact trial, conducted in the Democratic Republic of Congo, and describe some lessons learned, related to the definition of acceptable representative, the role of independent witness and the impact of (...) socio-economic vulnerability. To ensure children's protection, consent is required by the parents or, in their absence, by a legally mandated representative. In our setting, children's responsibility is often entrusted permanently or temporarily to relatives or friends without a tribunal mandate. Hence, a notion of ‘culturally acceptable representative’ under supervision of the local Ethics Committee may be more suitable. To ensure protection of illiterate subjects, an independent witness is required to confirm that the consent was freely given. However, in low-literacy contexts, potential witnesses often don't have any previous relationship with patient and there may be power-unbalance in their relationship, rather than genuine dialogue. In poor communities, trial participation may be seen as an opportunity to secure access to healthcare. Poverty may also lead to ‘competition’ to access the research-related benefits, with a risk of disturbance at societal or household level. Adjusting consent procedures to sociocultural and socioeconomic realities is essential for fulfilling the underlying ethical principles. This requires a collaborative dialogue between researchers, regulators and ethics committees. (shrink)