AbstractWhen the anionic dye acid red 137 (CI 17755) was applied to B-5 formalin fixed smears or tissues after clearing of the specimen in Lugol's solution and sodium thiosulfate, granules of eosinophils stained bright red orange. Most other cells stained pale cream color or not at all. Used as a selective stain for eosinophils, the stain holds promise as a means for quantitating eosinophils in urinary sediments, lymph node and bone marrow biopsies, as well as tissues such as liver, lung, gallbladder, and urinary bladder. (The J Histotechnol12:29, 1989.)