The purpose of this study is to explore the truth telling issue of patients with terminal cancer. Through reflecting the social and personal meaning on this issue from bioethics perspectives internationally or Taiwanese cultural characteristics nationally, it may own the possibility to facilitate and generate more effective indigenous knowledge and action in clinical ethics. The original participants in the large study were patients, family members, and health professionals, and the ways of data collection included 10 focus groups, 26 in-depth individual interviews, and above 23 field notes from multi-perspectives and multi-sites.This article is focused on exploring truth telling phenomenon within the doctor-patient relationship, which mainly adopted the approach of hermeneutic phenomenology. Three themes were emerged from the data analysis: (1) conflict between ethical principles and relational powers-the contrast between the medical authority and public humanity, (2) risky doctor-patient relationship-covering or disclosing bad news, (3) opening up the ethical development of professional autonomy-from medical authority to clinical expert. The results represent the encountered ethical dilemma with diverse ethical principles and particular cultural context of health professional-client relationship in Taiwan. Furthermore, this study tries to compare, analyze, and discover more realistic concepts and potential action for illness truth telling in clinics.