He weighed Koryo medicines with drugs manufactured in other countries for many years.

He then compiled "Hyangyakjipsongbang", a comprehensive book on Koryo medicines, together with his colleagues.

The book gives introductions, reasons, origins, symptoms and therapies of different diseases, as well as methods of applying acupuncture and moxibustion.

It also introduces hundreds of medicinal materials available in Korea, their growing areas, medicinal effects, and collection and application methods.

Ro also played a big role in compiling 365-volume "Uibangryuchwi", known as an encyclopedia of Koryo medicine.