Under tremendous financial pressure, many countries have adopted managed care or a similar technique as a method by which medical costs can be contained. However, experience in USA has shown that trust between physician and patient has become one of the most contentious issues under current managed care systems. Are the teachings and virtues of the Hippocratic Oath, which is the starting point of traditional medical ethics, sufficient to resolve conflicts that now face health professionals? It is the purpose of this article to introduce and discuss the concept and nature of “trust”. These will be used to propose potential ways, as recommended by medical ethics philosophers, by which the physician-patient relationship can be rebuilt. As Taiwan’s National Health Insurance is moving toward a type of managed care delivery system, these issues of trust deserve more attention in Taiwan.