Research laboratory group at Gif-sur-Yvette near Paris. In 1962 he was promoted to Director of Research. Around 1967, he established further research groups under his guidance; one at Orléans at the Marcel Delepine Center and a second at the Lannelogue Institute at Vanves. Scientific discoveries His research spread beyond chemical carcinogenesis. He also published widely in organic chemistry, pharmacology, therapeutics, epidemiology and biochemistry. He started his research career with investigations on chaulmoogric and hypocarpic acids in his Polytechnique laboratory. At the time, these were the only products used for treating leprosy. Within a few years, he had established himself as an international authority in the chemotherapy of the disease. He delineated the role of the cyclopentene ring and its double bond and of the chain length in determining the toxicity and leprostatic activity of these compounds. Although from the time of his 1944 meeting with Lacassagne onwards he was preoccupied with the study of chemical carcinogenesis, he continued to devote substantial effort to the chemotherapy of leprosy and the associated chemotherapy of tuberculosis. Chemical carcinogenesis The overwhelming amount of Bửu Hội's contributions are in the field of chemical carcinogenesis and the synthesis of related organic chemical compounds. In the late 1940s and early 1950s, he had extensive collaborations with the quantum chemistry personnel of the Radium Institute on various aspects of the electronic theory of carcinogenesis. Bửu Hội was the first to propose the involvement of noncovalent forces. Together with Lacassagne and Rudali, in the 1940s he became the first to describe the phenomena of synergisma and antagonism between carcinogens. He demonstrated this by using hydrocarbons on the skin of mice and later extended this to hepatic and other carcinogens. Starting in 1947, he collaborated with François Zajdela and Lacassagne in exploring the relationships between the structure and carcinogenic activity of polynuclear compounds. The study spanned a groundbreaking scale and depth. These involved the fundamental ring systems and derivatives of 1,2-benzanthracene, the dibenzopyrenes, steranthrenes, anthanthrene, 1,2,3,4-dibenzanthracene, a variety of benzo and dibenzofluoranthenes. This was extended to large-molecular-size and "hypercondensed" hydrocarbons, ring opening and partial hydrogenation. During his study of dibenzopyrenes, he discovered a molecular arrangement involving the framework of aromatic hydrocarbons. His studies of the carcinogenic azulenophenalenes led him to question the role of aromaticity. Aside from his studies with aza-replaced hydrocarbons, benz- and dibenzacridines and –carbazoles, he also synthesised and tested a number of new structural types of heteroaromatics