Aim of the study: We present and discuss a particular group of plants used by a diversity of healers in the initiation process and apprenticeship of traditional medicine, as practiced by Amazonian societies in East-Central Peru. Often, these plants are locally called plantas con madre (plants with a mother), and are thought to guide initiates in the process of seeking sacred knowledge, learning about plant usage, and understanding traditional medicine practices. We illustrate the diversity of plants used in the apprenticeship and practice of traditional medicine, and nurture the discussion to better understand the terminology used by Indigenous healers to describe plant uses and their practices. Materials and methods: The study was conducted between 2003 and 2008 with the participation of 29 curanderos (healers; 23 men, 6 women), 3 apprentices and 4 herbalists. The participants belonged to four ethnic groups: 17 Mestizos, 15 Shipibo-Konibo, 1 Ashaninka, and 1 Matsiguenga; a Spanish apprentice and an Italian herbalist were also included in the study. The field data were collected using semi-structured interviews, participant observation, and the witnessing of numerous healing sessions. Oral informed consent was obtained from each participant. Results: We identified 55 plant species belonging to 26 botanical families, which are used in initiation processes and apprenticeships of traditional medicine. This group of plants is administered under strict conditions during training and healing sessions called dietas (shamanic diets), with the supervision of one or more maestros curanderos (master healers). We observed that during the shamanic diets, maestros curanderos administered plants depending on the teachings or tools he/she was passing on, and were based on a particular sequence during the initiation process: (I) purification and cleansing species; (II) sensitivity and intuition; (III) strengthening; and (IV) protection and defence. Conclusions: Traditional healers continue to be a primary source of health care for the majority of the population in the Amazon region. Our research suggests that the system of dietas and the plantas con madre are fundamental components of the everyday practice of traditional medicine, maintenance of cultural continuity and Indigenous cosmovisions in the Amazonian societies in East-Central Peru. This paper contributes to filling the gap in the understanding of the process of initiation among healers in this area of the world. The study offers evidence of the need to collaborate with Indigenous healers to improve the recognition of their medical practices, role in their societies, and the value of their tools and medicines. A respectful attitude and open exchange of ideas and information may contribute to a better understanding of the language used by traditional medical practitioners, their practice, and their worldviews.