Gallnut (Mo Shi Zi), as one of the herbs popularly used in traditional Chinese medicine, came into China from Persia in the Northern Wei Dynasty. Gallnut was translated into different names from Persian into Chinese. This study attempted to identify its names, sources and nature by starting with Mo Shi Zi () and comparing with its relevant names Mo Shi Zi(),Ba Lv Zi () and Wu Bei Zi (). It was found that'', meaning black, in Mo Shi Zi () did not make sense because it neither matched the pronunciation in translation nor interpreted the medical meaning of Mo Shi Zi (). Mo Shi Zi () and Ba Lv Zi() were the same herb in traditional Chinese medicine. In Greek and Arabic classic books, Bullut referred to oak groups and their galls, but not Ba Lv Zi (). Ba Lv Zi () in these books referred to Omphacitis. Mo Shi Zi () referred to insect galls in the family of Quercus infectoriain Xi Yao Da Cheng, a book from overseas, and Wu Bei Zi ()appeared in the annotated text of Mo Shi Zi () as a similar herb. It was found that in traditional Chinese medicine, Mo Shi Zi () and Wu Bei Zi( ) were two different herbs, but could be interchanged in their medical nature.