The article suggests ways of dealing with the intricate discourse on »Jewish Diseases« from antiquity up to the present – both within and beyond anti-Semitism. Firstly, it presents a four-dimensional model that systemizes the different ways in which the sources talk about the subject. In employing this model the article develops images of Jews and Judaism constructed by them. Sec-ondly, the article distinguishes between a »documenting« and a »deconstructive« way in which the sources are used in the humanities. However, since sources dealing with »Jewish Diseases« are always biased and based on subjective prem-ises, the article pleads for investigating the latter. This even applies to the modern biomedical discourse, for instance on »genetic Jewish Diseases«, which promotes the biologisation and essentialisation of what it means to be Jewish.