The digestive system is a fundamental topic in biological science teaching. Despite its importance, the level of students' knowledge on the topic appears to differ from recommended levels at several educational grades. Their knowledge also seems to be resistant to change; therefore, this discrepancy may be viewed as an epistemological obstacle to teaching scientifically updated concepts related to the digestive system. Didactic-pedagogical resources are important tools for overcoming such difficulties. The present study was intended to analyse the use of a practical activity as a possible didactic resource to help (re)construct concepts regarding human digestive physiology and to amplify the conceptual profile of undergraduate students. Data collection was performed using questionnaires and semi-structured interviews to assess students' knowledge of the digestive system before and after participating in the practical activity. Qualitative data analysis revealed that previous knowledge was partially aligned with that described in the literature, suggesting a possible epistemological obstacle to teaching and learning scientific concepts. Participation in the activity not only contributed to better understanding of general aspects of the digestive system but also appeared to help overcome possible epistemological obstacles, including the role of the intestine.