In 1933 the Nazi regime passed the Civil Service Law, requiring all public servants to provide proof of Aryan ancestry. Frisch was unable to account for the ancestry of one of his grandparents, and was therefore Classified as a mischling of 1/8th Jewish ancestry, but formally allowed to keep his job. However groups of students and lecturers worked to have him dismissed from the university, preferring a committed National Socialist. Frisch also attracted negative attention for employing Jewish assistants, including many women, and for practicing "Jewish science". Eventually Frisch was forced into retirement, but the decision was reversed due to advances in his research on combating nosema infections in bees and his forced retirement was postponed until after the war. Frisch also worked actively to help Polish Scientists who had been singled out for internment by the Gestapo.