[7][8][user-generated source] In various newspaper articles it was reported that the couple in Vienna led a lively social life.

He received a crown pension of 20,000 Austro-Hungarian krones, which he donated to the Jewish Community of Vienna to support young doctors.

[12] He was a department head at the General Polyclinic Vienna, which he co-founded in 1872 alongside eleven other doctors, including Heinrich Auspitz, Carl von Rokitansky, Johann Schnitzler, Robert Ultzmann [de] and Wilhelm Winternitz.

[13] In 1872 Oser was appointed primary physician of the newly opened Rothschild Hospital for the Jewish Community of Vienna, which he ran until his death.

[11] In Vienna, cholera broke out due to the large number of visitors to the 1873 World's Fair and the inadequate sewage system.

In 1872 he was appointed head of the department of the General Polyclinic, and from 1873 he was a full member of the Lower Austrian State Medical Council, of which he was chairman from 1905.

[15] In 1896 he became co-editor of the journal Archiv für Verdauungskrankheiten mit Einschluß der Stoffwechselpathologie und Diätetik (Archive for Digestive Diseases including Metabolic Pathology and Dietetics), newly founded by Ismar Isidor Boas together with leading internists from international university hospitals who at that early stage had worked with digestive and metabolic diseases and had published monographs on the subject.

[16] It was not until 90 years later, in 1957, that the first fully flexible gastroscope found its way into gastroscopy, an invention of gastrologist Basil Isaac Hirschowitz and his technical director L. Curtiss, using fiberoptics.

[19] Oser and Wilhelm Schlesinger (1839–1896), a Hungarian-Austrian gynecologist working as a private lecturer in Vienna, made the innervation of the uterus the subject of their investigations and in 1872 demonstrated an excitation center in the medulla oblongata, which is located at the transition of the central nervous system to the spinal cord.