(also 606, Ehrlich 606), a medicinal antisyphili-tic preparation. It was synthesized in 1907 by the German scientists P. Ehrlich and A. Bertheim. The creation of salvarsan led to the establishment of chemotherapy. Salvarsan was only discovered after a prolonged period of research; it was the 606th in a series of tested preparations, from which its second name is derived. In 1909, Ehrlich and his student, the Japanese scientist S. Hata, successfully used salvarsan in treating syphilis. In modern medical practice salvarsan serves as the initial product in the manufacture of the antisyphilitic preparations myarsenol and neosalvarsan.