a laxative used in many preparations under various trade names; also used as an acid-base indicator in titrations involving weak acids and strong bases because it is brilliant red at high alkalinity and colorless below pH 8
A white or yellowish-white crystalline compound C₂₀H₁₄O₄ used in analysis as an indicator because its solution is brilliant red in alkalies and is decolorized by acids and in medicine as a laxative.