In adult rats administered simultaneously with potassium 82Br-bromide and 24Na-sodium chloride, we demonstrated the parallel course of the excretion rates of bromide and sodium ions with the aid of in vivo whole-body counting of the animals by high-resolution gamma-ray spectrometry. The rats were exposed to various intakes of sodium ions accompanied by five different anions: Br−, Cl−, HCO3−, ClO4−, and SCN−. Regardless of the anion accompanying the sodium ion, the excretion rates of 82Br− and 24Na+ ions were directly proportional to the magnitude of sodium intake in the rats.