Commemoration of the German Society of Gastroenterology
In memory of

Dr. med.
Karl Isaac-Krieger
1889 - 1969

Dr. med. Karl Isaac-Krieger © Leo Baeck Institute, New York
Dr. med. Karl Isaac-Krieger © Leo Baeck Institute, New York

Member since 1925

Training in gastroenterology with Leopold Kuttner in Berlin

Engaged with duodenal secretion analysis

Dissertation, Heidelberg 1913
Dissertation, Heidelberg 1913
Archiv für Verdauungs-Krankheiten, 1926
Archiv für Verdauungs-Krankheiten, 1926
Death notice, 1969 <br> © Leo Baeck Institute, New York
Death notice, 1969
© Leo Baeck Institute, New York

Dr. med. Karl Isaac-Krieger

  • Cologne, 1‌0‌.‌0‌5‌.‌1‌8‌8‌9‌
  • New York, 2‌5‌.‌0‌3‌.‌1‌9‌6‌9‌
  • Member since 1925
  • Escaped to the USA in 1938
  • Berlin
  • Specialist in gastrointestinal and metabolic diseases in private practice

“I, Karl Isaac, was born in Cologne on the Rhine on 10 May 1889 as the son of the factory owner Isidor Isaac and his wife Anna Philippine, née Straus. After attending a preparatory school for three years, I started at the Königliches Friedrich-Wilhelms-Gymnasium (Royal Friedrich Wilhelm Grammar School) in Cologne on Easter 1898, from which I graduated on Easter 1907 with the certificate of maturity,” Karl Isaac states in the curriculum vitae included in his dissertation.


Education and Places of Work

Isaac-Krieger studied one semester in Göttingen, five semesters in Berlin, then in Heidelberg, Munich, and Bonn. He passed the state examination in Bonn on Easter 1912. Isaac was a medical trainee at the Medical Clinic of the Karlsruhe Municipal Hospital from June to December 1912. He worked for Hugo Starck, the first describer of the “Starcksche Sonde” (Starck probe) and a founding member of the (D)GVS. He then moved to Heidelberg to the University Women’s Clinic. Isaac received his doctorate from the University of Heidelberg on 7 August 1913 with the thesis “Aktinomykose und Compressionsmyelitis”.

Dissertation, Heidelberg 1913
Dissertation, Heidelberg 1913

He started his training in internal medicine at the I. Medical Clinic of the Rudolf Virchow Hospital (RVK) in Berlin on 1 July 1914 under Leopold Kuttner, who supported him considerably in the years to come. His training was interrupted by the First World War, in which Isaac actively participated. He again worked for Kuttner at the I. Medical Clinic of the RVK from February 1919 to 31 March 1925. Thereafter Isaac-Krieger settled in Berlin as a specialist in gastrointestinal and metabolic diseases. He had been using the name Isaac-Krieger since 1920.

Isaac-Krieger worked and published on pancreatic enzymes in stool and duodenal secretions, on duodenal secretion analysis, occult blood in the stool, ulcer therapy, and dietary treatment, among other things, in the Archive for Digestive Diseases (“Boas Archiv”). He also ran nutrition courses at the Lette House in Berlin.


Archiv für Verdauungs-Krankheiten, 1926
Archiv für Verdauungs-Krankheiten, 1926


Isaac-Krieger lost his health insurance licence as early as 1933. His appeals and petitions against this decision were all rejected, the last one in May 1934.


Escape to the USA via England in 1938

Isaac-Krieger fled Berlin on 22 September 1938, initially to England, where his son Gerhard had already emigrated to in 1937. Karl Isaac-Krieger, his wife, and their 17-year-old daughter were able to travel from Southampton to the USA aboard the S.S. Washington on 4 November 1938. They reached New York on 10 November 1938. The son initially remained in England and later moved to the USA.

Isaac-Krieger received a licence to practise medicine in New York in November 1939, after having passed language tests and redoing his medical examinations. He was also an active adjunct at Lenox Hill Hospital and Beth Israel Hospital in New York. He referred to himself as Charles Isaac-Krieger in the USA.

He was a member of the American College of Gastroenterology and the Rudolf Virchow Medical Society in the City of New York.

Charles Isaac-Krieger died in New York on 25 March 1969 at the age of 79.

Death notice, 1969 <br> © Leo Baeck Institute, New York
Death notice, 1969
© Leo Baeck Institute, New York


  1. Theoretisches und Klinisches über die Pankreasfermente in den Faeces und im Duodenalsaft, insbesondere über den Nachweis des Trypsins. Arch Verdauungskr 1920; 26: 351-364
  2. Zur Frage der Brauchbarkeit der Sekretionsprüfung des Magens mit der Verweilsonde. Arch Verdauungskr 1926; 37: 442-54 (Festschrift zum 60. Geburtstag Leopold Kuttners)
  3. Mit Kuttner L.: Über abdominelle Schmerzzustände. Slg Abh Verd-Stoffw , Hermann Strauß [Hg], Band 1, Heft 3, 2. neubearb. Aufl., Halle: C. Marhold Verlagsbuchhandlung 1926
  4. Mit Kuttner L. u. Kwilecki D.: Ernährung , Diätküche, Kostform. Berlin: Julius Springer Verlag, 1930 (Handbücherei des gesamten Krankenhauses Bd. 6)

Sources and Further Reading


Biographie of Dr. med. Karl Isaac-Krieger


  • Leo Baeck Institute New York und Center of Jewish History. Leon Dinkin Collection.CJH, AR 5608
  • Staatsbibliothek Berlin. Isaac K. Dissertation: Aktinomykose und Compressionsmyelitis. Heidelberg; 1913. SBB-SPK, Sign. Ja 8380-1913,2: 28f.


  • Forsbach R, Hofer H-G. Internisten in Diktatur und junger Demokratie. Die Deutsche Gesellschaft für Innere Medizin 1933-1970. Berlin: Medizinisch Wissenschaftliche Verlagsgesellschaft 2018: 423
  • Schwoch R. Berliner Jüdische Kassenärzte und ihr Schicksal im Nationalsozialismus. Ein Gedenkbuch. Berlin: Hentrich & Hentrich Verlag 2009: 380


  • Ancestry Ireland Unlimited Company. ancestry (Recherche zu Geburts- und Sterbedaten sowie zu den Schiffs-Passiergierlisten Europa-USA). Im Internet:; Stand: 25.11.2020

  • Kirche Jesu Christi der Heiligen der Letzten Tage. FamilySearch. Im Internet:, Stand: 15.05.2021