This research envisioned as its main objective the comprehension of the process of knowledge production concerning the Afro-Brazilian boldo ("Plectranthus barbatus Andrews"), with the contributions from both scientists and the Afro-Brazilian people. As specific objectives, we attempted to reconstruct the research pathways traveled by medicinal plant scientists and by the Afro-Brazilian people and to evaluate the conduct of scientists along this process. The method exploited in this investigation consisted of a systematic literature review followed by content analysis from a bardanian perspective. Within the framework of this investigation (decoloniality of knowledge), the theories of epistemicide, epistemic pillage, and ethics of Ubuntu comprise the main theoretical constructs employed. During content analysis, we formulated a category discussing how the ancestral wisdom was presented in the papers investigated herein. The process of knowledge production always occurs in collaboration with other scientists, which, according to the theory of Ubuntu, can be considered ethical. We analyzed how the ancestral knowledge is presented in the research papers related to boldo in order to understand both its influence on the body of research examined and the possible processes of epistemic injustice. It is possible that, in the process of knowledge production depicted herein, Afro-Brazilian people might have had their epistemes pillaged, which appears to be unethical under the perspective of Ubuntu theory, and this motivated, in this work, the proposal of an ethically oriented process of knowledge production. This research first establishes the approaches between ethical and epistemological aspects with respect to processes of knowledge production, from a decolonial perspective, and reveals the nuances of those processes, the epistemic injustices that have occurred, and the ethical problems due to these injustices.