In modern society, people are expected to make scientific decisions and rational actions over a range of personal and social problems. There have been a number of studies on students' and adults' decision-making over socio-scientific issues under the name of scientific literacy. In this study, we investigated the social and cultural backgrounds of Korean people's actions and trust over their personal problems (e.g. health, career choice), by conducting in-depth interviews with ten Korean adults on their experience related to acupuncture and Four Pillars of Destiny (FPD), two representative examples of unorthodox sciences. The analysis of the data reveals that their actions concerning acupuncture and FPD are influenced by socio-cultural factors (esp. family culture, social system) and by their understandings of the nature of science. In addition, we found that there are a different set of reasons and varying degrees of people's trust between acupuncture and FPD. Based on the results, we discussed the needs to introduce wider concepts of the nature of science and of the scopes of science education.