Pillai spent nearly 16 years collecting material for the
Tamil-English Dictionary of Medicine, Chemistry, Botany, and Applied Sciences. In 1938, he compiled and published two volumes of his work at his own expense, but could only partially publish the third volume. The remaining part was published with assistance from the
Government of Tamil Nadu. The fourth and fifth volumes were published in 1977 and 1978, respectively by
G. D. Naidu and his son G. D. N. Gopal. Pillai's dictionary provides information about plants, minerals, metals, and animals used in
Siddha medicine. Consisting of five volumes, it spans 6,537 pages and contains nearly 80,000 words. The work provides translations for Tamil words in English and describes and explains each word with appropriate annotations. The dictionary was renamed
The Greatness of Siddha Medicine and was published at the second
World Tamil Research Conference, held in Chennai in 1968. The dictionary is cited in academic research related to Siddha medicine and Tamil literature. ==References==