tetrabromophenolphthalein sodium

tet·ra·bro·mo·phe·nol·phthal·ein so·di·um

(tet'ră-brō'mō-fē'nol-thal'ēn sō'dē-ŭm),
The sodium salt of a brominated dye; it was used early in the development of cholecystography.