Phenolphthalein is widely used as an indicator in acid-base titrations, water treatment applications. Due to its pH sensitivity, It is used to the check extend of carbonation in concrete, soap and in toys as diapering work. It is used in Kastle-Meyer test, which identifies the substances containing blood.

This Thermo Scientific Chemicals brand product was originally part of the Alfa Aesar product portfolio. Some documentation and label information may refer to the legacy brand. The original Alfa Aesar product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.