Carl Peter Thunberg, a Swedish medical doctor and botanist who visited Japan in 1775 as a medical doctor attached to the Dutch Trade House in Dejima, Nagasaki, taught the treatment of syphilis using mercury water to Japanese doctors and interpreters. This therapy is based on the oral administration of a 0.014% solution of mercuric chloride and was published in 1754 by Gerard van Swieten in Vienna, who questioned the utility of the conventional salivation therapy. The dose was set taking safety into account. Kogyu Yoshio, a Japanese-Dutch interpreter, had already read about it in a book written by J. J. Plenck, when he was taught about the therapy by Thunberg. He recorded Thunberg's teachings in his book "Komohijiki", presenting details of various formulations, including a high-dose formulation. The mercury therapy was subsequently spread across the country by medical doctors who learned Western medicine through the Dutch. In the 1820's, Genshin Udagawa, who read a number of Western medical books, published books on Western drugs. In these books, G. Udagawa included precise information on "Swieten Yakushu-hu (medicated alcohol)", including information on the dosage, formulation, mode of usage, and precautions for use. The maximum dose of mercuric chloride established chloride established by van Swieten was included in the Japanese Pharmacopoeia up to its 5th edition.