This is the last part of the monograph about the theriaka (treacle), a famous antidote invented by ancient Greeks, This part is composed of five sections. The first and the second ones deal with the routes of the diffusion of this drug in the societeis of Medieval Europe, and the writer thinks that the main route should be from the arabian medical world through Spain and Italy, especially Sicily. The third section, "The Portuguese and the Theriaka in India ", quotes some paragraphs of " The Simples and Drugs of India" by Garcia da Orta (c. 1490-c. 1570), and the writer tries to show the diffusion of the theriaka in the Islamic society of India during the 16 th century. The fourth section is assigned to this antidote brought by the Portuguese to Japan in the 16 th century. Finally in the fifth section, the last and the longest, the writer discusses about the heriaka brought by the Dutch during T.okugawa Period, and also about the works concerning this medicine, wrote by several Japanese scholars. Especially, the writer introduces two interesting manuscripts preserved in the Library of Kyoto University. Both of the two are anonymous. But the first one seems to be written by a Japanese scholar who learned medicine from some Dutch physician who came to Nagasaki probably in the period from the 18 th to the first half of the 19 th century, and the contents of this mantscript are the prescriptions of twenty-six kinds of theriaka The second one is the very naive translaion into Japanese of an advertising statement of a pharmacist of Venice probably in medieval age. The writer guesses that the translator of this note has the possibility to be identified with one of Yoshio family, very renowned lineage of interpreters of Dutch lauguage at Nagasaki and represented by Kogyu Yoshio (1724-1800) who flourished during the second half of the 18th century. In the conclusive part of this essay, the writer expresse his astonishment at the fact that such a supersticious drug as the theriaka could be so highly estimated and expanded among the peoples of Europe, Asia and Africa for nearly two thonsand years, in spite of the amazing development of human knowledges and civilizations.