"Eau de Javel" (liquid bleach) is a common cause of chromate contact allergy. A historical review explains the reasons for the addition of sodium dichromate after the First World War. The chromium content in different brands of eau de Javel has been determined by flameless atomic absorption spectrophotometry. The results indicate that the chromium content is very low (0.03--3.65 mg/l) in French brands, whereas it is still important (7.06--82.9 mg/l) in Belgian brands, such an observation indicates that the almost complete removal of chromate in most brands of French eaux de Javel is a good example of prevention in the field of contact dermato-alllergology.