Amounts of rhodamine B (RhB) accumulated in 48 hpf zebrafish embryos when also exposed to different concentrations of various chemicals. These compounds comprised the synthetic musk fragrances galaxolide and tonalide, the polycyclic aromatic hydrocarbon phenanthrene, the ABCB1 inhibitor verapamil and the ABCB1 substrate vinblastine. Galaxolide, tonalide and phenanthrene are ecotoxicologically relevant chemicals. Embryos were exposed to RhB and simultaneously to either of these compounds. Values are means +/− standard deviations from three independent experiments. Statistically significant differences from controls were determined with one-way analysis of variance (ANOVA), followed by Dunnett’s test and are indicated by asterisks (P <0.05).