The project generated ecotoxicological data needed for the development of a tailored testing strategy to assess the environmental risk of pharmaceuticals (progestins and glucocorticoids). For this purpose, chronic fish tests, among others, were carried out in the laboratory according to a new test protocol currently undergoing OECD validation investigating dienogest and dexamethasone as test substances. The studies provided reliable and valid results with effect thresholds in the lower µg/L or ng/L range. This has closed data gaps for the development of new assessment approaches for a targeted risk assessment of specifically acting pharmaceuticals. Additional investigations on directed gene expression and immunosuppressive effect assays would complement the assessment strategy for progestins and glucocorticoids.