Beliefs about the causes of illnesses have had implications on how individuals and society responds to sicknesses and epidemics. These beliefs have been derived from the process of observation, test, selection, and transfer through generations in the quest to preserve a harmony between man and the physical and social environments. There are three Thai beliefs influencing health and diseases: 1) The balance between four elements (soil, water, wind and fire); 2) supernatural; and 3) beliefs about faith and astrological. Different societies (local and national) have accumulated, collated, and summarized the experiences of their responses into national and local wisdoms. Some of the wisdoms are documented, while others remained as folk knowledge. Objective: This article describes some examples of how Thai wisdom and folk knowledge have changed overtime and how it might influence decisions to accept modern medicine in Thai society.