Although the government in Vietnam intends to develop an
identifiable Vietnamese Medical Science, traditional medicine
has existed for generations. There are three medical traditions
which have coexisted in Vietnam prior to the impact of Western
Medicine: these are Thuoc Bac (Northern Medicine), Thuoc Nam
(Southern Medicine), and Thuoc Tay (Western Medicine). With
Thuoc Bac or Northern Medicine only those Vietnamese capable of
reading Chinese characters could diagnose and prescribe
remedies. Northern medicine began with the belief that out of
Yin-Yang force interactions and the eight trigrams, one could
construct a model of the entire universe, valid on both material
and moral planes. The human body was thus a microcosmic
reproduction of the vast dynamic natural forces at work in the
universe. The body was intimately and constantly linked to those
external forces, so that good health depended in large part on
tuning internal functions to the environment, as well as
building defenses against disruptive changes