It has been widely assumed that Vietnamese traditional medical practices were governed by Chinese medical texts and theories, whether it was the practice of one or another of the two main branches of medicine in Vietnam (
the northernor Chinese branch and 
the southern orindigenous one). However, as Michele Thompson points out, Nôm, or demotic Vietnamese script, held a significant place in the literate transmission of medical knowledge. Exploring texts written in different languages and scripts concerning smallpox, and combining them with historical data, ethnographic observations and extensive documentation, she has questioned a common belief. Thereby Vietnamese Traditional Medicine also gives some new insights into the circulation of medical traditions between China and Vietnam.
To draw a contrast with Chinese and Vietnamese medical traditions, Thompson first makes a detour through the introduction of a Western prophylactic method, the Jennerian or smallpox vaccination, in the Vietnamese imperial court at the beginning of the 1920s (Chapter 2). In her narrative, she skilfully combines global facts, such as the history of vaccine invention and circulation, and local ones. She pays particular attention to the chronology of the event at the imperial court of Hue, tracing the career of a central figure, Jean-Marie Despiau, the French medical doctor who brought back the vaccine from Macao. Significantly, his mission was launched at the accession to the throne of Minh Mang, the second of the Nguyên dynasty, who shortly afterwards restructured the Vietnamese royal medical service on the Chinese model and prohibited the use of Nôm. While M. Thompson emphasises the rapid adoption of the Western method, she notices that variolation, an older preventive measure, practised in particular by Chinese physicians, only appeared in Vietnamese medical texts after the introduction of the vaccine. She argues that the Chinese dominant theory of taidu, or congenital foetal poison, that is to say an inborn factor, as the cause of smallpox conflicted with the Vietnamese aetiology. The practice of variolation would have been accepted only once reviewed in the light of the Western theory of an external factor at the origin of the disease, in accordance with the Vietnamese explanation. As shown in earlier studies, Chinese physicians could adopt vaccination by reinterpreting it in terms of their own theory, a parallel which reinforces the argument.
The divergence between the Chinese and Vietnamese theories and practices is further explored in Chapter 3. M. Thompson brings together personal data, with more general observations, like the close relation between aetiological beliefs and medical practices in any society. For most Vietnamese practitioners, she says, external factors, such as climate, played a prominent role in disease aetiology, especially in the case of epidemic diseases. Moreover, a comparison of the Chinese-style variolation with the variolation procedures used by the Vietnamese, as recorded by French colonial doctors, leads to the conclusion that the latter did not inherit the method from the Chinese. But, Thompson’s most original contribution certainly comes from her research into medical texts, in particular with her philological study of the Chinese character for du (in tai du or ‘poison’). She suggests a significant difference between its meaning and use by the Chinese and by the Vietnamese, which would have reinforced the rejection of the tai du theory among the latter. Finally, she questions why after 1920, while Minh Mang allowed only the use of Chinese in the royal medical service, variolation, as well as vaccination, were mostly discussed outside the palace in Nôm texts or in the texts with a mixture of Chinese and Nôm (Hán-Nôm). Although she could only hypothesise – she argues some kind of ‘discomfort’ with Chinese-type variolation among the physicians of the royal service –, this raises the issue of the social hierarchy among the physicians established under Minh Mang and to its close relation with the script used, Chinese vs Nôm.
As is mentioned several times in the book, traditional healers practising indigenous medicine were also pharmacists, as well as botanists, renowned for their competence in this domain in China, which had incorporated a considerable number of Vietnamese drugs in its pharmacopeia. In Chapter 4, in her discussion on plant nomenclature in Nôm, Thompson shows that the construction of Nôm characters was guided by taxonomic principles. While the script, sometimes mixed with Chinese characters, was the main vehicle of family transmission of medical knowledge, she examines the expansion of 
(romanised Vietnamese) and the decline of publications in Nôm under French colonial rule. Finally, the changing status of indigenous healers is analysed in relation to the emergence of a Western-trained medical elite, of the role of 
as a new instrument of anti-Frenchresistance, and of the nationalist movement, which leads to the rehabilitation of their knowledge.
Certainly, the present situation is no longer exactly how Thompson describes it. The industrial processing and development of traditional medicinal products as well as population movements, especially to the cities, have, at least partly, deprived traditional practitioners of their knowledge. In any event, this book covering two decisive centuries, and very well documented, offers an innovative view of Vietnamese medical practices, and especially of the close relations between language and medicine. While it does not minimise the great influence of Chinese medicine, it opens new directions of research into the circulation of scientific ideas between China and Vietnam.
